5.4: Aslak Lie Cupboard
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Cupboard
Norwegian-American Aslak Olsen Lie, c.1860 Wood (pine), glass, metal Gift of Ella Mavis MHAHS 1984.011.0001 |
In the collection held by the Mount Horeb Historical Society in Wisconsin there is an old stepback cupboard. Made of pine and painted red, the item dates to the late 1860s or early 1870s. Its straight lines and glazed upper doors related to the style of cupboards typical in America at that time. However, the curved wings that flank the step on each side point toward Norwegian stylistic influence. The raised diamond panels of the lower casement doors indicate the cabinet to be the work of local craftsman Aslak Lie.
The work of Aslak Lie, a 19th century Norwegian cabinetmaker who immigrated to Wisconsin, can be assessed both in light of style and construction. Spanning six decades, Lie’s career straddled the Atlantic Ocean, offering a case study in the influences of immigration on the creative output of an individual artisan. A 50-year old man when he emigrated, Lie came to Wisconsin an already mature craftsman. Tracing the corpus of his work through Norway and Wisconsin reveals the complex interplay of personal artistic style and changing expression.
Aslak Olsen Lie: Early Life In Norway and Immigration
Aslak Lie was born in 1798 to husmenn, tenant farmer, parents in Reinli, Vladres, Norway. Reinli is a village within the municipality of Sør-Aurdal. Valdres is a mountainous, inland region in south-central Norway, situated halfway between Oslo and Bergen and oriented along the Begna River valley. [1] Even as the Coalition Wars brought tough economic conditions to Norway, Lie’s family was particularly poor. [2] The plot of land they farmed was situated on a northwestward-facing slope, which received less sun and retained snow for a month longer than southeastward-facing farms across the valley. [3] The fifth child and fatherless at the age of twelve, perhaps Aslak Lie’s only advantage was that he possessed some schooling. With no public schools in Norway at that time, Lie received only a modest education from itinerant schoolteachers and confirmation classes. Still, he learned well enough to read and write.
Aslak Lie enrolled in the Aurdal Company of the Valdres Musketeer Corps on November first, 1819. [4] Twenty-one years old, Lie was given the rank of corporal, a non-commissioned officer whose duty included keeping the company’s records and maintaining equipment. The job required service for only a few days of the year and paid just a small stipend, but the post conferred upon Lie some degree of respectability and provided him with a rare means of upward social mobility. Moreover, with nearly no evidence as to how Lie acquired his skills as a craftsman, military training, or connections he made through his service, are possible avenues through which he learned. An inscription he made on the stock of a hand plane places Lie in Christiana on August fifth of the following year. [5] When signing his name on the plane, Lie included his rank in the military. The plane suggests that he was in the city learning the cabinetry trade and assembling his own set of tools, but there are no records indicating how long he was in the city. The quality of the decorative floral carving on the plane indicates that he had at least become practiced by the time he made it in August. The impact that Christiana’s urban fashions had on his work for the rest of his life also suggests that Lie spent a considerable amount of time there, absorbing the principles of what was considered to be good design. It was also perhaps here that he started to develop his ideas of artistry and artistic identity.
However long Aslak Lie spent in Christiana, he was back in Sør-Aurdal by 1824 and beginning his career as an artisan. Beginning in that, year he aided in the construction of a belltower for the village church in Bagn, on which project he also demonstrated that he knew ironworking. [6] That year Lie was also hired to build four drop-front desks, each of which he signed on the bottom side of a drawer. Signing his work made Lie unique as a furniture-maker in Valdres at this time. By signing the pieces he made, often accompanied by the date, his title as corporal, and, in some instances, a note, Lie seems to have been trying to advertise his skills and gain notoriety. Over the course of his career, Lie’s use of his signature changed. Early on, he signed most pieces he worked on, but as he matured and innovating with his own designs, his signature appeared only on those works that he seems to have felt he exercised his creativity. [7] Lie’s self-conscious use of his signature appears to belie an aspiration to be recognized as an artist and achieve a higher social standing.
In 1826, Lie took two major steps in his life. The first was signing a contract to become a husmann . [8] On January fourth, Lie entered into a lease for a small tract of uncultivated land adjoining the Sondre Lie farm. In exchange for use of the land, Aslak Olsen Lie was required to work for the owner of the property, Ole Olsen Brenden, for several weeks a year and pay him a number of bushels of produce. Lie built a cottage on the sight, put the land to plow, and called the site “Nerli.” [9] Then on June 16th, he got married to Marit Knutsdatter Døven. Eight years his junior, Marit was the daughter of one of the wealthiest farm owners in Valdres. However, the Døven family had nearly twenty children and Marit was one of the youngest of them. Consequently the dowry she brought to the marriage was relatively modest compared to the size of her family’s farm, but her status brought with her connections to future clients of Aslak’s furniture.
The family spent ten years at Nerli, during which time Aslak Lie continued to receive a variety of commissions. He was employed by the Bagn church and its parishioners several more times, improving its balcony and adding decorative carvings to the organ and interior. [10] He also continued to innovate, coming up with new ways to use and modify traditional Norwegian folk motifs. He made frequent use of elaborate acanthus and floral carvings, which, while out of style in the urban areas, were still popular among rural communities in Norway. His secretaries usually bear a signature design on the front of the drop-leaf. Comprising of two, highly stylized, carved rosettes, Lie seems to have taken inspiration from a rococo, 8-shaped pattern common on cupboards in the Vladres region. [11] Lie’s design proved popular and he made a number of secretaries with variations on this design during his career in Norway. However, by the middle of the 1830s, he seems to have started feeling confined by the demand for the pattern. This is evidenced by the decline in frequency with which he signed these pieces. [12] In works he made for himself, Lie’s work exhibits experimentation with different designs and motifs and particularly a growing interest in diamonds, or lozenges.
In 1836, the Lie family saved up enough money that they bought their own piece of land on the more affluent side of the Begna valley. The property, called “Motet,” was situated near the main road between Bergen and Christiana and had a site for a mill. [13] Three children were born to Aslak and Merit while they lived at Nerli, two of whom survived. At Motet, they welcomed four more children, all of whom lived into adulthood. In 1837, Aslak built a large, new house on his new property. This house was a major departure from the typical homes in Valdres at the time. Rather than building it according to a rectangular floor-plan, Aslak Lie added an ell to the footprint. The exterior gallery, rather than extending to cover the whole façade of the house, only spanned a part of it. Lie’s interest in diamonds in pervasive in the building; he rotated the square, gable windows onto their points, installed a diamond-shaped plaque with a blessing above the door, and added a diamond and rectangle wooden pattern to the ceiling of the parlor. In the large, center diamond of this pattern, Lie put up an iron plate with a hook, from which to hand a lamp. However, magnificent as this house and property was, the family seems to have faced difficulties. According to tradition, the Lie family faced such a shortage of food at one point that Aslak dismantled and sold the lock to the house for food. [14]
Emigration of people from Valdres to the United States started in the early 1840s. Norway’s growing population, coupled with a weak domestic economy, fueled the mass migration of people out of Norway. [15] Letters, articles, and other testimonies from Norwegians who had gone to the United States circulated back within Norway, tempting others with the allure of economic prosperity and social advancement. Two men, Gul Guttormsen Ildjernstadhaugen and Stephen Olsen Kubakke immigrated from Valdres to Wisconsin in 1843 and 1846, respectively. Kubakke returned to Valdres two years later and set up a party for settlement. At the same time, an article by Thore Spaanem, published in the Norwegian newspaper Nordlyset , convinced Aslak Olsen Lie to emigrate himself. [16] Lie set out with forty other members of the Valdres community to establish a new settlement in Wisconsin. The party set out from Bergen aboard the barque Augusta, arriving in New York Harbor on June 29th, 1848. Lie turned fifty while aboard the Augusta , accompanied by his wife, Marit, and all six of their children: Ingrid (21), Marit Oline (17), Ole (13), Knut (11), Halvor (6), and Ole (3). [17] Also in the group were Aslak’s childless brother and sister-in-law, Ole Olsen Lie and Anne Olsdatter, as well as both Ingrid and Marit Oline’s future husbands.
From New York, the party proceeded to Milwaukee, and finally to the Blue Mounds region of southern Wisconsin. Here the group settled in the township of Springdale, within Dane County. This original group, with Lie at its center, established the foundation upon which a successive chain of immigration of Norwegians from the Valdres region to the Blue Mounds was based. Here, as in Norway, Lie pursued his cabinetry with the goal of achieving greater artistic expression and economic security.
The Thompson Family Furniture
The stepback cupboard in the Mount Horeb Historical Society’s collection was passed down through the Skindrud-Thompson family. [18] The cupboard is one of a number of Lie pieces that the family owned. Many of these other pieces are also in the Historical Society’s possession and include a secretary, drop-leaf table, another cupboard, and an Empire-style sofa. [19] Lie originally made the secretary for his eldest son, Ole. [20] Lie often gave pieces like this as wedding presents, as he did with his other sons, Halvor, for whom he made a parquet secretary, and Knut, whom he gave a corner cupboard with a rounded front. [21] Based on this, it is probable that Aslak Lie made this secretary as a wedding gift to Ole and his bride, Dordei Guttenborg, which would place the date of the object to 1855. [22] Less than a year into their marriage, however, Ole died of disease, though not before the couple conceived a son. Dordei remarried in 1858 to Eric Skinrud. Lie likely produced the other aforementioned pieces for Dordei and Eric. [23] From them, the furniture passed to a daughter, who married into the Thompson family, which is how the pieces ended up in the Thompson farmhouse, where they were when the Mount Horeb Historical Society acquired them.
According to the descendants who owned the pieces, the stepback cupboard was jointly built by Aslak Olsen Lie and Eric Skinrud. [24] However, there are no other works attributed to Skinrud, nor is there any indication that he was otherwise engaged in cabinetmaking. Without other known works to compare the cupboard to, it is very difficult to say for certain whether he did have a hand in making it. The only induction that two people may have been involved in making the piece is that the back boards are joined using two different methods. One of the joints fits together in a tongue and groove. The other joint is a half lap. The existence of two types of joints like this does not prove that two people worked on the piece, but it implies it suggests that there may be something to the family’s story.
There is an alternative explanation for the story as well, which is that Eric Skinrud repaired the cupboard and this was misremembered in his family as him having been involved with building it originally. Support for this possibility is that the back does show signs suggestive of repair. There are three boards that are awkwardly placed, extending only part way up the cupboard and cutting across part of another board. These pieces are narrower, lighter, and have a smoother surface than the other boards that make up the back. These traits generally imply that a piece of wood is not as old as the rest of the piece. Of course, it is also possible that Skinrud both helped Lie make the cupboard and later repaired it. In any case, however, all aspects of the cupboard point to Aslak Lie having been primarily responsible for its form and construction.
The Mount Horeb Stepbak Cupboard and Immigrant Form
With a career that lasted roughly sixty years, Aslak Olsen Lie produced a sizable body of works over the course of his lifetime. Because he spent roughly thirty years of that career on either side of the Atlantic, comparing Lie’s works from Norway and Wisconsin illustrates how his style was changed and transformed as part of the process of acculturating to American society. Looking at a selection of the furniture Lie made in America reveals that his works fall on a spectrum of Norwegian and American styles. Rather than progressing according to a linear timeline on which his output becomes more and more American, Lie moved between styles regularly depending upon what the circumstances called for.
A cupboard Aslak Lie made for John and Birthe Engesæthe in 1870 is a prime example of one of his Norwegian pieces. [25] The cupboard is a typical form found in Norway with agled corners on the base, similar to a trapezoid, and a deep hutch and a rectangular top. Though formalistically similar to the cupboards he made earlier while in Valdres, Lie brought the form into a more updated style with a flat top and decoration with dominant use of straight lines. The drawers are red with painted versions of his signature diamond pattern. Still, within the rectangular fields in the cupboard doors, Lie has decorated the piece with rose painting. Lie’s dominant red and blue paint also speak to traditional Norwegian norms.
In contrast, a chest of drawers Lie made sometime after 1878 illustrates his ability to work in an American mode. The turned feet and corner posts, double drawers on the top row, as well as the proportions, speak to the Sheraton influence on the piece. Meanwhile, the alternating bands of reeding on the corner pillars, saw-tooth frieze, and curved handles are all elements Lie has drawn from the Egyptian Revival. Made primarily of walnut, the color of the wood itself is meant to serve as decoration. This is something Lie rarely did with his Norwegian pieces, but is common in American furniture. Within this piece, Lie’s personal voice remains present, demonstrated by the large raised diamonds on either side of the piece as well as his use of secret compartments.
Living within a mixed Norwegian and American community, Lie cultivated the ability to alternate between styles as a means of appealing to consumers’ tastes. In an advertisement Lie put out in a local newspaper in 1870, he promoted himself on his ability to make furniture in both American and European fashions. [26] In this flexibility, Aslak Lie displayed what might be termed artistic code switching wherein he was able to shift from one vocabulary to another depending on his situation. Just as rural tastes limited him in Valdres, the commercial considerations of what the Springdale community wanted shaped Lie’s work in America. Beyond the constraints of his customers’ ethnicity and tastes, Lie also found himself constrained economically by what his customers could afford. [27] Where Lie had hoped his customers in America would have allowed him to innovate on luxury pieces, he more often found himself making simple, unadorned furniture.
Another process was happening in Lie’s work between these two styles – the synthesizing of the two influences to create a distinctly Norwegian-American style of furniture. The majority of Lie’s work in Wisconsin shows some degree of this hybridization. Here, too, Lie may have been responding to the gradual acculturation of Springdale’s Norwegian immigrants into American society. However, the presence of this hybridization in pieces Lie made for his own family, as well as other evidence of Lies sense of American identity, suggest a personal transformation was taking place. The stepback cupboard that Lie made for the Skindrud family is one example of this both societal and personal transformation.
The overall form of the Mount Horeb stepback cupboard is American in character. At 75 inches tall, the stepback at the waist is thirty-seven inches off the ground. The lower portion of the case is nineteen and a half inches deep, while the upper portion is eleven and three-eighths inches deep. The entire cupboard is forty-five and three-fourths inches wide. The bottom of the cupboard opens with two frame and panel doors. The twin doors of the upper casement, on the other hand, are glazed, each one comprised of six square panes divided into two columns and three rows. Simple bands of moulding with both edges rounded run around the top and waist of the piece. A wider compound moulding runs about the base. The doors of the bottom panels include Lie’s signature diamond pattern, an ornamentation that bridges American and Norwegian styles.
The stepback cupboard is a common American form. They appear in America in the 17th century and remained common up into the 20th century. The glazed upper doors originated in the 18th century as a way for the well-to-do to display their china. The proportions of the Mount Horeb stepback cupboard reflect common American conventions with the waist at or below half the total height of the cupboard. The rectangular base is also American and counterpoised with both the angular bases of the Engesæthe cupboard as well as other cupboards Lie made in Norway.
While cupboards with deeper lower casements and shallower upper casements are found in Norwegian design, those examples differ from the Mount Horeb stepback. On the Engesæthe and Valdres cupboards Lie made, the base juts out by virtue of the angled sides. [28] Likewise in examples in that style, a hutch separating the lower and upper cabinets is ubiquitous. Because of the inward angle of the base, frequently the lower cabinet has a single, panel door. Norwegian cupboard also often have drawers between the lower cabinet and hutch.
Though the casework conforms to American sensibilities, Lie ornamented the cupboard with a number of Norwegian elements. The curved wings on either side of the stepped shelf harken to elements found in traditional Norwegian cupboards. The S-shaped slope and bump-shape of the wings of the stepback cupboard is nearly the same progression of curves that frame the sides of the hutch on the Engesæthe cupboard. To accommodate the wings, Lie diverged from the construction of an American stepback where the sides are composed of two boards; one the width of the top cupboard extending the entire height of the piece, and the other running from the base to the step only as wide as the base comes forward. Lie widened the taller side piece so he could cut out the wing and enclose part of the step. That is to say, the shorter board is narrower and emerges above the step to form the bump in the wing.
Lie also eschews the use of feet as is common on American stepback cupboards. Instead the base rests wholly on the floor, as is the norm for Norwegian cupboards. Likewise, the original color scheme for the Mount Horeb cupboard was red outside while the interiors and top of the step are painted blue. This, again, appeals more to Norwegian tastes than to American.
While Wisconsin afforded Lie fewer opportunities for extravagant artisanship than he had hoped, he was nevertheless able to experiment and push boundaries in new ways. The process of stylistic hybridization was itself a creative action. Lie created new designs out of elements he knew from both Norway and America. He was still able to show creative self-expression through his cabinetry. While not as elaborate or fine as the secretaries Lie made in Valdres, the Mount Horeb stepback cupboard is an example of individual artistic growth. Lie took joy in interpreting his customers’ and his relations’ tastes and ethnic identities to determine what balance of influence he should use in specific pieces.
Technique and Tradition
In form and style, Aslak Olsen Lie’s post-immigration works display a great variation as he actively interpreted his neighbors’ and his own ethnic identity. At a more structured level, however, Lie’s furniture retained a more consistently Norwegian character. The techniques and habits that Aslak Lie pick up as a young man in Norway stayed with him for his entire life and were present in his pieces regardless of style.
Lie’s dovetails are illustrative of both the Norwegian tradition he worked in as well as his own unique idiosyncrasies. Lie made his pins and tails to be roughly equal in size. He tended to cut the two at a roughly twenty degree angle. However, on smaller drawers, such as those that made up the insides of drop-leaf desks, Lie would cut one side of a tail at an angle, while the other he cut straight. What distinguished his dovetails was his use of wedges. After fitting pins and tails, Lie would take a chisel and knock two notches in the end grain of the pins. He made each of these notches at an angle parallel to the side of the pin it was nearest to. Then he hammered a small wedge into the notches, firming the faces of the pins up to the tails and making the joint fast. Incredibly, Lie used this technique even on half-blind dovetails.
The technique of using wedges to fasten dovetails instead of glue is found in cabinetry traditions of Germany and Norway, and thus shows up in some American furniture from Pennsylvania and Wisconsin. [29] However, it is alien to the Anglo-American craftsman. Most craftsmen using this method only use a single wedge in each pin. Lie’s double wedges at angle were an artistic flair all his own. Lie used this technique regularly; it can be found on the carcass of the Mount Horeb stepback cupboard and drawers of the secretary he made for his son, Ole. Significantly, it even shows up on the late-career, Egyptian Revival chest of drawers.
Through training and practice, the techniques that an artisan such as lie used became habit. [30] As they worked, they would follow the steps that come naturally to them through muscle memory. Thus, even while the immigrant Lie used his head to innovate and alternate styles, his body followed the same, distinctly Norwegian, patterns of work that he had done for decades. This, too, then was an expression of ethnic identity and one that remained largely unchanged even as other parts of Lie’s work became Americanized.
Conclusion
Consideration of the life and work of Aslak Lie shows that on an aesthetic level he actively shapes his identity as a Norwegian-American craftsman, but in his techniques he retains his Norwegian identity. As a case study, Aslak Lie demonstrates how the process of acculturation and hybridization among first generation immigrants is an active process. Lie’s consciously shaped and used ethnic character to navigate his new market. By so doing, he pushed his own artistic boundaries, as well as both Norwegian and American furniture to new forms. Simultaneously, Lie’s retention of his native construction traditions shows ethnicity to work on many levels, not all of which are equally subject to change in a new environment. Habitualized practices, such as those that make up the individual actions involved in making, are deeply in-grained within the individual.
Lie is one example of the immigrant experience. Immigration is ripe for analysis with a Material Culture approach because it reflects ethnic identity of the maker. Considering the work of someone like Lie is a way of understanding how he navigated the immigrant experience in 19th century rural America.
Going forward, the example of Lie’s retention of culturally-bound techniques raises questions about the ability of such practices to be transmitted and continued by successive generations within immigrant communities. Whether they survive, mutate, or disappear is a question about the long-term durability of distinct ethnic identity. Their study also can inform how new practices are introduced, disseminated, and assimilated by the dominant culture. Ultimately, work identifying and tracking individual Norwegian artisans such as Aslak Lie is only in its infancy. Further investigation is required to determine whether the example of Aslak Lie is typical of the immigrant artisan or whether his own artistic attitudes and circumstances make him unique. In any case, the quality and character of Lie’s production warrant study and analysis in their own right.
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Andrew A Veblen,
The Valdris Book: A Manual of the Valdris Samband
(Minneapolis: Andrew A. Veblen, 1920, 15. The city of Oslo was called Christiana until the early twentieth century. As the events discussed in this paper took place prior to that change, it will be otherwise be referred to by its old name.
↵
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Reidar Bakken,
Snikkaren Aslak Olsen Lie: Bygdekunstnar i Valdres og Wisconsin 1798-1886, Craftsman on two Continents
(Oslo: Novus forlag, 2000), 135.
↵
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John O. Holzhueter, “Aslak Lie and the Challenge of the Artifact,”
The Wisconsin Magazine of History,
Vol. 70, No. 1 (Autumn, 1986): 6-7, JSTOR (4636013).
↵
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Discharge Certificate of Aslak Lie, December 31, 1847, box 1, biographical folder, John Holzhueter Papers, translated by Alice Alderman.
↵
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Bakken, 23.
↵
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Holzhueter, 8.
↵
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Bakken, 136.
↵
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Holzhueter, 10.
↵
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Bakken, 135.
↵
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Bakken, 39-43.
↵
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Ibid, 25. ↵
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Ibid, 137. ↵
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Holzhueter, 12. ↵
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Bakken, 140. ↵
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Ibid, 140. ↵
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Terje Mikael Haste Joranger,
The Migration of Tradition? A Study on the Transfer of Traditions Tied to Intergenerational Land Transfers among Emigrants from the Valdres region, Norway to the Upper Midwest and their Descendants for Three Generations, 1850-1980
(Oslo: University of Oslo, 2008), 188. ↵
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Bakken, 140. ↵
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Cupboard, Wisconsin Decorative Arts Database
,
last modified March 19, 2008,
http://content.wisconsinhistory.org/...a/id/546/rec/5
. ↵
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Desk and bookcase, Wisconsin Decorative Arts Database, last modified March 19, 2008,
http://content.wisconsinhistory.org/.../id/542/rec/14
. Table, Wisconsin Decorative Arts Database, last modified July 22, 20078,
http://content.wisconsinhistory.org/cdm/compoundobject/collection/wda/id/249/rec/7
. Cupboard, Wisconsin Decorative Arts Database, last modified March 19, 2008,
http://content.wisconsinhistory.org/cdm/compoundobject/collection/wda/id/223/rec/6
. Bakken, 100.
↵
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Bakken, 109. John Holzhueter, interview with the author, December 2, 2016.
↵
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Halvor A. Lee family negatives, circa 1865-1935, folder 1, Wisconsin Historical Society Archives. Bakken, 111.
↵
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Amelia I. J. Pope,
Dentennial History Township of Springdale, Dane County, Wisconsin
(Madison: 1948), 14.
↵
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John Holzhueter, interview with the author, December 2, 2016.
↵
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Ibid.
↵
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Bakken, 117.
↵
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Letter, Brian J. Bigler to Marion Nelson, January 25, 1999, Aslak Olsen Lie Folder, Mount Horeb Historical Society Archives.
↵
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Bakken, 142.
↵
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Bakken, 57, 117.
↵
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“Wedged Dovetails,”
millcreek woodworking,
August 9, 2012,
https://millcrek.wordpress.com/2012/...ged-dovetails/
.
↵
-
Robert Tarule,
The Artisan of Ipswich: Craftsmanship and Community in Colonial New England
(Baltimore: John Hopkins University Press, 2004), 142.
↵


2.3: What is the Appropriate Use of Curiosity
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Selections from Confessions and Commentary on the Metaphysics of Aristotle
Augustine & Thomas Aquinas
In this section, you will find two passages. The first is from Augustine's Confessions. He frames his version of what it means to be curious. In the second passage, you will find a passage from Aquinas' Commentary on the Metaphysics of Aristotle. In that passage, he lays out his competing vision of what it means to be curious.
54. At this point I mention another form of temptation, more various and dangerous. For over and above that lust of the flesh which lies in the delight of all our senses and pleasures—whoso slaves are wasted unto destruction as they go from You—there can also be in the mind itself, through those same bodily senses, a certain vain desire and curiosity, not of taking delight in the body, but of making experiments with the body’s aid, and cloaked under the name of learning and knowledge. Because this is in the appetite to know, and the eyes are the chief of the senses we use for attaining knowledge, it is called in Scripture the lust of the eyes. For “to see” belongs as a property to the eyes; yet we apply the word also to the other senses, when we use them for gaining knowledge. Thus we do not say: “Hear how it flashes,” or “Smell how bright it is,” or “Taste how it shines,” or “Touch how it glows”: because all these things are said to be seen. Yet we do not say only “See how it shines,” something that only the eye can perceive; but also “See how it sounds,” “See how it smells,” “See how it tastes,” “See how hot it is.” Thus the experience of the senses as a whole, as has been said, is called the lust of the eyes, yet we apply it to the other senses by analogy when they are in pursuit of the truth about anything.
55. In this it is easy to distinguish between the way in which the senses serve pleasure and the way in which they serve curiosity. Pleasure goes after objects that are beautiful to see, hear, smell, taste, touch, but curiosity for the sake of experiment can go after quite contrary things, not in order to experience their unpleasantness, but through the mere itch to experience and find out. What pleasure can there be in seeing a mangled corpse, which is only horrible? yet if there happens to be one anywhere about, people flock to it to be saddened and sickened: indeed they are in terror that they may dream about it. So that you would think that when they are awake they would not go to see it unless either they were dragged there by force, or some false report that the sight was beautiful had drawn them. It is the same with the other senses which it would be long to follow up. Because of this disease of curiosity you have the various freaks shown in the theatres. Thus men proceed to investigate the phenomena of nature—the part of nature external to us—though the knowledge is of no value to them: for they wish to know simply for the sake of knowing. We have a similar thing when for the sake of the same perverted learning inquiry is made by way of magic. And the same happens even in religion: God is tempted when signs and wonders are demanded, not for any purpose of salvation, but solely for the experience of seeing them.
Reflection Question
Few today would frame "experiment" in such a negative light, but Augustine raises an interesting question. What is the limit to the type of things that you can justify learning just because you wanted to know them? Can I find out your social security number just because I want to know?
1. [Aristotle] says, first, that the desire to know belongs by nature to all men.
2. Three reasons can be given for this. The first is that each thing naturally desires its own perfection. Hence matter is also said to desire form as any imperfect thing desires its perfection. Therefore, since the intellect, by which man is what he is, considered in itself is all things potentially, and becomes them actually only through knowledge, because the intellect is none of the things that exist before it understands them, as is stated in Book III of The Soul; so each man naturally desires knowledge just as matter desires form.
3. The second reason is that each thing has a natural inclination to perform its proper operation, as something hot is naturally inclined to heat, and something heavy to be moved downwards. Now the proper operation of man as man is to understand, for by reason of this he differs from all other things. Hence the desire of man is naturally inclined to understand, and therefore to possess scientific knowledge.
4. The third reason is that it is desirable for each thing to be united to its source, since it is in this that the perfection of each thing consists. This is also the reason why circular motion is the most perfect motion, as is proved in Book VIII of the Physics, because its terminus is united to its starting-point. Now it is only by means of his intellect that man is united to the separate substances, which are the source of the human intellect and that to which the human intellect is related as something imperfect to something perfect. It is for this reason, too, that the ultimate happiness of man consists in this union. Therefore man naturally desires to know.
Reflection Question
What do you see as the main points of contrast between Augustine and Aquinas?


15.3: Free Fall
An important example of motion with (approximately) constant acceleration is provided by free fall near the surface of the Earth. We say that an object is in “free fall” when the only force acting on it is the force of gravity (the word “fall” here may be a bit misleading, since the object could actually be moving upwards some of the time, if it has been thrown straight up, for instance). The space station is in free fall, but because it is nowhere near the surface of the earth its direction of motion (and hence its acceleration, regarded as a two-dimensional vector) is constantly changing. Right next to the surface of the earth, on the other hand, the planet’s curvature is pretty much negligible and gravity provides an approximately constant, vertical acceleration, which, in the absence of other forces, turns out to be the same for every object , regardless of its size, shape, or weight.
The above result—that, in the absence of other forces, all objects should fall to the earth at the same rate, regardless of how big or heavy they are—is so contrary to our common experience that it took many centuries to discover it. The key, of course, as with the law of inertia, is to realize that, under normal circumstances, frictional forces are, in fact, acting all the time, so an object falling through the atmosphere is never really in “free” fall: there is always, at a minimum, and in addition to the force of gravity, an air drag force that opposes its motion. The magnitude of this force does depend on the object’s size and shape (basically, on how “aerodynamic” the object is); and thus a golf ball, for instance, falls much faster than a flat sheet of paper. Yet, if you crumple up the sheet of paper till it has the same size and shape as the golf ball, you can see for yourself that they do fall at approximately the same rate! The equality can never be exact, however, unless you get rid completely of air drag, either by doing the experiment in an evacuated tube, or (in a somewhat extreme way), by doing it on the surface of the moon, as the Apollo 15 astronauts did with a hammer and a feather back in 1971 2 .
This still leaves us with something of a mystery, however: the force of gravity is the only force known to have the property that it imparts all objects the same acceleration, regardless of their mass or constitution. A way to put this technically is that the force of gravity on an object is proportional to that object’s inertial mass , a quantity that we will introduce properly in the next chapter. For the time being, we will simply record here that this acceleration, near the surface of the earth, has a magnitude of approximately 9.8 m/s 2 , a quantity that is denoted by the symbol \(g\). Thus, if we take the upwards direction as positive (as is usually done), we get for the acceleration of an object in free fall \(a = −g\), and the equations of motion become
\[ \Delta v=-g \Delta t \label{eq:2.15} \]
\[ \Delta y=v_{i} \Delta t-\frac{1}{2} g(\Delta t)^{2} \label{eq:2.16} \]
where I have used \(y\) instead of \(x\) for the position coordinate, since that is a more common choice for a vertical axis. Note that we could as well have chosen the downward direction as positive, and that may be a more natural choice in some problems. Regardless, the quantity \(g\) is always defined to be positive: \(g\) = 9.8 m/s 2 . The acceleration, then, is \(g\) or \(−g\), depending on which direction we take to be positive
In practice, the value of \(g\) changes a little from place to place around the earth, for various reasons (it is somewhat sensitive to the density of the ground below you, and it decreases as you climb higher away from the center of the earth). In a later chapter we will see how to calculate the value of \(g\) from the mass and radius of the earth, and also how to calculate the equivalent quantity for other planets.
In the meantime, we can use equations like (\ref{eq:2.15}) and (\ref{eq:2.16}) to answer a number of interesting questions about objects thrown or dropped straight up or down (always, of course, assuming that air drag is negligible). For instance, back at the beginning of this chapter I mentioned that if I dropped an object it might take about half a second to hit the ground. If you use Equation (\ref{eq:2.16}) with \(v_i\) = 0 (since I am dropping the object, not throwing it down, its initial velocity is zero), and substitute \(\Delta t\) = 0.5 s, you get \(\Delta y\) = 1.23 m (about 4 feet). This is a reasonable height from which to drop something.
On the other hand, you may note that half a second is not a very long time in which to make accurate observations (especially if you do not have modern electronic equipment), and as a result of that there was considerable confusion for many centuries as to the precise way in which objects fell. Some people believed that the speed did increase in some way as the object fell, while others appear to have believed that an object dropped would “instantaneously” (that is, at soon as it left your hand) acquire some speed and keep that unchanged all the way down. In reality, in the presence of air drag, what happens is a combination of both: initially the speed increases at an approximately constant rate (free, or nearly free fall), but the drag force increases with the speed as well, until eventually it balances out the force of gravity, and from that point on the speed does not increase anymore: we say that the object has reached “terminal velocity.” Some objects reach terminal velocity almost instantly, whereas others (the more “aerodynamic” ones) may take a long time to do so. This accounts for the confusion that prevailed before Galileo’s experiments in the early 1600’s.
2 The video of this is available online: https://www.youtube.com/watch?v=oYEgdZ3iEKA . It is, however, pretty low resolution and hard to see. A very impressive modern-day demonstration involving feathers and a bowling ball in a completely evacuated (airless) room is available here: https://www.youtube.com/watch?v=E43-CfukEgs .


12.1: Soil Profiles and Processes
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What is Soil?
The word “ soil ” has been defined differently by different scientific disciplines. In agriculture and horticulture, soil generally refers to the medium for plant growth, typically material within the upper meter or two (Figure \(\PageIndex{1}\)). We will use this definition in this chapter. Soil consists predominantly of mineral matter, but also contains organic matter ( humus ) and living organisms. The pore spaces between mineral grains are filled with varying proportions of water and air.
In common usage, the term soil is sometimes restricted to only the dark topsoil in which we plant our seeds or vegetables. In a more broad definition, civil engineers use the term soil for any unconsolidated (soft when wet) material that is not considered bedrock. Under this definition, soil can be as much as several hundred feet thick! Ancient soils, sometimes buried and preserved in the subsurface, are referred to as paleosols (Figure \(\PageIndex{2}\)) and reflect past climatic and environmental conditions.
Importance of Soil
Soil is important to our society primarily because it provides the foundation of agriculture and forestry. Of course, soil is also a critical component for terrestrial ecosystems, and thus important to animals, plants, fungi, and microorganisms.
Soil plays a role in nearly all biogeochemical cycles on the Earth’s surface. Global cycling of key elements such as carbon (C), nitrogen (N), sulfur (S), and phosphorous (P) all pass through soil. In the hydrologic cycle, soil helps to mediate the flow of precipitation from the surface into the groundwater. Microorganisms living in soil can also be important components of biogeochemical cycles through the action of decomposition and other processes such as nitrogen fixation.
Soil Forming Factors
The fundamental factors that affect soil genesis can be categorized into five elements: climate, organisms, relief, parent material, and time. One could say that the relief, climate, and organisms dictate the local soil environment and act together to cause weathering and mixing of the soil parent material over time. As soil is formed it often has distinct layers, which are formally described as “horizons.” Upper horizons (labeled as the A and O horizons) are richer in organic material and so are important in plant growth, while deeper layers (such as the B and C horizons) retain more of the original features of the bedrock below (Figure \(\PageIndex{3}\)).
Climate
The role of climate in soil development includes aspects of temperature and precipitation. Soils in very cold areas with permafrost conditions tend to be shallow and weakly developed due to the short growing season. Organic rich surface horizons are common in low-lying areas due to limited decomposition. In warm, tropical soils, soils tend to be thicker, with extensive leaching and mineral alteration. In such climates, organic matter decomposition and chemical weathering occur at an accelerated rate.
Organisms
Animals, plants, and microorganisms all have important roles in soil development processes, in providing a supply of organic matter, and/or in nutrient cycling. Worms, nematodes, termites, ants, gophers, moles, etc. all cause considerable mixing of soil and help to blend soil, aerate and lighten the soil by creating pores (which help store water and air).
Plant life provides organic matter to soil and helps to recycle nutrients with uptake by roots in the subsurface. The type of plant life that occurs in a given area, such as types of trees or grasses, depends on the climate, along with parent material and soil type. With the annual dropping of leaves and needles, trees tend to add organic matter to soil surfaces, helping to create a thin, organic-rich A or O horizon over time. Grasses, on the other hand, have a considerable root and surface masses that add to the soil each fall for annuals and short-lived perennials. For this reason, grassland soils have much thicker A horizons with higher organic matter contents, and are more agriculturally productive than forest soils.
Relief (Topography and Drainage)
The local landscape can have a surprisingly strong effect on the soils that form on site. The local topography ( relief ) can have important microclimatic effects as well as affecting rates of soil erosion. In comparison to flat regions, areas with steep slopes overall have more soil erosion, more runoff of rainwater, and less water infiltration, all of which lead to more limited soil development in very hilly or mountainous areas. In the northern hemisphere, south-facing slopes are exposed to more direct sunlight angles and are thus warmer and drier than north-facing slopes. The cooler, moister north-facing slopes have a more dynamic plant community due to less evapotranspiration and, consequently, experience less erosion because of plant rooting of soil and have thicker soil development.
Soil drainage affects organic matter accumulation and preservation, and local vegetation types. Well-drained soils, generally on hills or sideslopes, are more brownish or reddish due to conversion of ferrous iron (Fe 2+ ) to minerals with ferric (Fe 3+ ) iron. More poorly drained soils, in lowland, alluvial plains or upland depressions, tend more be more greyish, greenish-grey (gleyed), or dark colored, due to iron reduction (to Fe 2+ ) and accumulation and preservation of organic matter in areas tending towards anoxic. Areas with poor drainage also tend to be lowlands into which soil material may wash and accumulate from surrounding uplands, often resulting in overthickened A or O horizons. In contrast, steeply sloping areas in highlands may experience erosion and have thinner surface horizons.
Parent Material
The parent material of a soil is the material from which the soil has developed, whether it be river sands, shoreline deposits, glacial deposits, or various types of bedrock. In youthful soils, the parent material has a clear connection to the soil type and has significant influence. Over time, as weathering processes deepen, mix, and alter the soil, the parent material becomes less recognizable as chemical, physical, and biological processes take their effect. The type of parent material may also affect the rapidity of soil development. Parent materials that are highly weatherable (such as volcanic ash) will transform more quickly into highly developed soils, whereas parent materials that are quartz-rich, for example, will take longer to develop. Parent materials also provide nutrients to plants and can affect soil internal drainage (e.g. clay is more impermeable than sand and impedes drainage).
Time
In general, soil profiles tend to become thicker (deeper), more developed, and more altered over time. However, the rate of change is greater for soils in youthful stages of development. The degree of soil alteration and deepening slows with time and at some point, after tens or hundreds of thousands of years, may approach an equilibrium condition where erosion and deepening (removals and additions) become balanced. Young soils (< 10,000 years old) are strongly influenced by parent material and typically develop horizons and character rapidly. Moderate age soils (roughly 10,000 to 500,000 years old) are slowing in profile development and deepening, and may begin to approach equilibrium conditions. Old soils (>500,000 years old) have generally reached their limit as far as soil horizonation and physical structure, but may continue to alter chemically or mineralogically.
Soil development is not always continual. Geologic events can rapidly bury soils (landslides, glacier advance, lake transgression), can cause removal or truncation of soils (rivers, shorelines) or can cause soil renewal with additions of slowly deposited sediment that add to the soil (wind or floodplain deposits). Biological mixing can sometimes cause soil regression, a reversal or bump in the road for the normal path of increasing development over time.
Contributors and Attributions
- Essentials of Environmental Science by Kamala Doršner is licensed under CC BY 4.0. Modified from the original by Matthew R. Fisher.


11.9: Gramática. Repaso los verbos irregulares en la forma de “yo”
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- Romano Sánchez Domínguez
- Imperial Valley College
Objetivos
- Recognize the correct conjugations of verbs that have irregularities in the yo form
You have learned so far that there are some regular verbs that simply add the ending to suit their subject, other verbs with changes in the stem vowel, and other totally irregular verbs. In addition to these conjugations, there is a group of verbs that may be regular, irregular, stem changers *and* have an irregularity in their yo (first person singular) form.
Vamos a ver cuáles son esos verbos…
|
Tener
(
to have
)
‘Yo’ and stem changer |
Hacer
(
to make/to do
)
Regular other than ‘yo’ |
Salir
(
to leave, to go out
)
Regular other than ‘yo’ |
Traer
(
to bring
)
Regular other than ‘yo’ |
Venir
(
to come
)
‘Yo’ and stem changer |
Valer
(
to be worth
)
Regular other than ‘yo’ |
Poner
(
to put
)
Regular other than ‘yo’ |
Seguir
(
to follow
)
‘Yo’ and stem changer |
Decir
(
to say, to tell
)
‘Yo’ and stem changer |
| tengo | hago | salgo | traigo | vengo | valgo | pongo | sigo | digo |
| tienes | haces | sales | traes | vienes | vales | pones | sigues | dices |
| tiene | hace | sale | trae | viene | vale | pone | sigue | dice |
| tenemos | hacemos | salimos | traemos | venimos | valemos | ponemos | seguimos | decimos |
| tenéis | hacéis | salís | traéis | venís | valéis | ponéis | seguís | decís |
| tienen | hacen | salen | traen | vienen | valen | ponen | siguen | dicen |
|
Oír
(
to hear
)
Irregular, has “y” in some forms because of three vowels together: “i” in the middle becomes a “y” sound, and an accent mark is needed at other times to separate the weak and strong vowels. |
Ver
(
to see
)
Regular other than ‘yo’, but note that accent mark is not needed for vosotros form, since it is one syllable. |
Dar
(
to give
)
Regular other than ‘yo’, but note that accent mark is not needed for vosotros form, since it is one syllable. |
| oigo | veo | doy |
| oyes | ves | das |
| oye | ve | da |
| oímos | vemos | damos |
| oís | veis | dais |
| oyen | ven | dan |
Contributors and Attributions
- Gramática: Verbos irregulares en la forma de “yo”. Authored by : SUNY Oneonta with Lumen Learning. Provided by : SUNY Oneonta. License : CC BY: Attribution


1.11: Key Roles in a Retail Business
- Identify key roles within retail businesses
There are a myriad of roles within the retail environment. Before we take a deep dive into the career opportunities, let’s explore why one would choose a career in retail. What are some of the reasons you are interested in retail? If you haven’t considered it why might you consider it? As you watch the video below can you relate to what is said?
You can view the transcript for “Why Choose a Career in Retail?” (opens in new window).
The retail industry offers diverse and unique career paths where you could work for some of the world’s most recognizable brands. Many of the main goals of retail— be it sales and profitability, product innovation, or customer relationships—intersect with other career fields like marketing, finance, technology, loss prevention, merchandising and management. Whether in stores or corporate headquarters many of key roles in retail include internal coordination, planning and logistics, store operations, human resources / training, finance and administration, buying, marketing, logistics, and information technology.
Positions in the retail industry can largely depend on what the company or store is selling. All positions must have some knowledge or familiarity with the products they sell and the needs of customers. At the forefront of the retail team are entry-level positions that tend to have the most face to face time with customers and tend to make up the bulk of the workforce of a company. Positions at this level could be a cashier, stocker, front end or sales associate. Entry level positions do not require a worker to supervise other workers at the same entry level positions.
The next level up would be intermediate management that supervises entry level and other staff. With diverse roles and departments in the retail industry there is a need for distinct types of management to direct and accommodate different areas and departments:
- Human resource management
- Operations management or production management
- Strategic management
- Marketing management
- Financial management
- Information technology management (responsible for the management information systems)
Management in general is the act of engaging with an organization’s human talent and using the physical resources at a manager’s disposal to accomplish desired goals and objectives efficiently and effectively. Management comprises planning, organizing, staffing, leading, directing, and controlling an organization (a group of one or more people or entities) or effort for the purpose of accomplishing a goal.
One of the most important duties for a manager is effectively using an organization’s resources. This duty involves deploying and manipulating human resources (or human capital), as well as efficiently allocating the organization’s financial, technological, and natural resources. Since organizations can be viewed as systems, management can also be defined as human action, such as product design, that enables the system to produce useful outcomes.
Basic Functions
Management operates through various functions, such as planning, organizing, staffing, leading/directing, controlling/monitoring, and motivating.
- Planning: Deciding what needs to happen in the future (today, next week, next month, next year, over the next five years, etc.) and generating plans for action.
- Organizing: Implementing a pattern of relationships among workers and making optimum use of the resources required to enable the successful carrying out of plans.
- Staffing: Job analysis, recruitment, and hiring of people with the necessary skills for appropriate jobs. Providing or facilitating ongoing training, if necessary, to keep skills current.
- Leading/directing: Determining what needs to be done in a situation and getting people to do it.
- Controlling/monitoring: Checking current outcomes against forecast plans and making adjustments when necessary so that goals are achieved.
- Motivating: Motivation is a basic function of management because without motivation, employees may feel disconnected from their work and the organization, which can lead to ineffective performance. If managers do not motivate their employees, they may not feel their work is contributing to the overall goals of the organization (which are usually set by top-level management).
Depending on the size of the store and the company structure there will be different types and levels of managerial positions.Most organizations have three management levels: first-level, middle-level, and top-level managers. These managers are classified according to a hierarchy of authority and perform different tasks. In many organizations, the number of managers in each level gives the organization a pyramid structure.
Middle-level managers can include general managers, branch managers, and department managers. They are accountable to the top-level management for their department’s function, and they devote more time to organizational and directional functions than upper management.
A middle manager’s role may emphasize:
- Executing organizational plans in conformance with the company’s policies and the objectives of the top management.
- Defining and discussing information and policies from top management to lower management.
- Most importantly, inspiring and providing guidance to lower-level managers to assist them in performance improvement and accomplishment of business objectives.These positions seldom involve any customer contact.
Some examples of middle management in the retail industry include:
- Merchandise Manager
- Assistant Store Manager
- Customer Service Manager
- District Sales Manager
- Food or Product department Manager
- Sales Manager
- Store or warehouse Manager
Additional Resources
- For more information on management and theory, see Principles of Management.
- For an extensive list of manger types and titles check out these articles on Retail Job Titles and Descriptions and Types of Jobs in Retail
Contributors and Attributions
- Management. Provided by : Wikipedia. Located at : https://en.wikipedia.org/wiki/Management . License : CC BY-SA: Attribution-ShareAlike
- Mary Parker Follett. Provided by : Wikimedia. Located at : https://commons.wikimedia.org/wiki/File:Mary_Parker_Follett_(1868-1933).jpg . License : CC BY-SA: Attribution-ShareAlike
- Middle Management . Provided by : Wikipedia. Located at : http://en.wikipedia.org/wiki/Middle_management . License : CC BY-SA: Attribution-ShareAlike
- Why Choose a Career in Retail - CEO, SVP, Marketing. Authored by : Sephora Life. Located at : https://youtu.be/U74NtPa8AdQ . License : All Rights Reserved . License Terms : Standard YouTube License


19.5: Evaluate Nutritional Strategies to Impact Musculoskeletal and Integumentary Wellness
By the end of this section, you should be able to:
- 19.4.1 Evaluate a nutritional plan for its effectiveness on musculoskeletal and integumentary wellness.
- 19.4.2 Modify a nutritional plan to promote musculoskeletal and integumentary wellness.
Evaluating the Client’s Compliance with the Meal Plan
Evaluation is an important part of the nursing process. After the client has integrated nutritional strategies into their eating habits, the nurse should go back and evaluate the effectiveness of the plan. This is accomplished through objective and subjective findings. Barriers to compliance may include a client’s inability to read, write, and perform simple math. Finances, resources, transportation, and support are also barriers to client nutritional compliance.
A client’s compliance with the meal plan can, to some degree, be evaluated through their improvement of symptoms related to the musculoskeletal and integumentary systems. Objective ways to evaluate compliance with a meal plan are monitoring client weight and laboratory test results. Other objective findings include improvement in wounds, fractures, injuries, and nail and hair quality. Radiology procedures showing regeneration of bone or no extension in bone loss are also objective findings.
Subjective data from the client or caregivers must also be considered in determining client nutritional compliance. In other words, the nurse needs to listen to the client and caregivers to determine if compliance is being met.
Evaluating the Effectiveness of a Nutritional Plan
The effectiveness of a nutritional plan can be determined by many factors such as weight variance, changes in pain and edema, alterations in muscle strength and tone, and absence or presence of fatigue. DEXA (dual x-ray absorptiometry) scans that measure bone density can be used as a follow up to the initial scan to determine if bone loss is stable or progressing. Continual monitoring of client labs is an effective way to evaluate whether the nutritional plan is working. Labs for the musculoskeletal and integumentary systems are outlined in Table 19.9.
| Labs for Musculoskeletal and Integumentary Systems | Indications |
|---|---|
|
|
|
|
|
|
|
|
|
|


12.E: Fluid Dynamics and Its Biological and Medical Applications (Exercises)
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Conceptual Questions
12.1: Flow Rate and Its Relation to Velocity
1. What is the difference between flow rate and fluid velocity? How are they related?
2. Many figures in the text show streamlines. Explain why fluid velocity is greatest where streamlines are closest together. (Hint: Consider the relationship between fluid velocity and the cross-sectional area through which it flows.)
3. Identify some substances that are incompressible and some that are not.
12.2: Bernoulli’s Equation
4. You can squirt water a considerably greater distance by placing your thumb over the end of a garden hose and then releasing, than by leaving it completely uncovered. Explain how this works.
5. Water is shot nearly vertically upward in a decorative fountain and the stream is observed to broaden as it rises. Conversely, a stream of water falling straight down from a faucet narrows. Explain why, and discuss whether surface tension enhances or reduces the effect in each case.
6. Look back to Figure. Answer the following two questions. Why is \(\displaystyle P_o\) less than atmospheric? Why is \(\displaystyle P_o\) greater than \(\displaystyle P_i\)?
7. Give an example of entrainment not mentioned in the text.
8. Many entrainment devices have a constriction, called a Venturi, such as shown in Figure. How does this bolster entrainment?
A tube with a narrow segment designed to enhance entrainment is called a Venturi. These are very commonly used in carburetors and aspirators.
9. Some chimney pipes have a T-shape, with a crosspiece on top that helps draw up gases whenever there is even a slight breeze. Explain how this works in terms of Bernoulli’s principle.
10. Is there a limit to the height to which an entrainment device can raise a fluid? Explain your answer.
11. Why is it preferable for airplanes to take off into the wind rather than with the wind?
12. Roofs are sometimes pushed off vertically during a tropical cyclone, and buildings sometimes explode outward when hit by a tornado. Use Bernoulli’s principle to explain these phenomena.
13. Why does a sailboat need a keel?
14. It is dangerous to stand close to railroad tracks when a rapidly moving commuter train passes. Explain why atmospheric pressure would push you toward the moving train.
15. Water pressure inside a hose nozzle can be less than atmospheric pressure due to the Bernoulli effect. Explain in terms of energy how the water can emerge from the nozzle against the opposing atmospheric pressure.
16. A perfume bottle or atomizer sprays a fluid that is in the bottle. (Figure.) How does the fluid rise up in the vertical tube in the bottle?
Atomizer: perfume bottle with tube to carry perfume up through the bottle. (credit: Antonia Foy, Flickr)
17. If you lower the window on a car while moving, an empty plastic bag can sometimes fly out the window. Why does this happen?
12.3: The Most General Applications of Bernoulli’s Equation
18. Based on Bernoulli’s equation, what are three forms of energy in a fluid? (Note that these forms are conservative, unlike heat transfer and other dissipative forms not included in Bernoulli’s equation.)
19. Water that has emerged from a hose into the atmosphere has a gauge pressure of zero. Why? When you put your hand in front of the emerging stream you feel a force, yet the water’s gauge pressure is zero. Explain where the force comes from in terms of energy.
20. The old rubber boot shown in Figure has two leaks. To what maximum height can the water squirt from Leak 1? How does the velocity of water emerging from Leak 2 differ from that of leak 1? Explain your responses in terms of energy.
Water emerges from two leaks in an old boot.
21. Water pressure inside a hose nozzle can be less than atmospheric pressure due to the Bernoulli effect. Explain in terms of energy how the water can emerge from the nozzle against the opposing atmospheric pressure.
12.4: Viscosity and Laminar Flow; Poiseuille’s Law
22. Explain why the viscosity of a liquid decreases with temperature—that is, how might increased temperature reduce the effects of cohesive forces in a liquid? Also explain why the viscosity of a gas increases with temperature—that is, how does increased gas temperature create more collisions between atoms and molecules?
23. When paddling a canoe upstream, it is wisest to travel as near to the shore as possible. When canoeing downstream, it may be best to stay near the middle. Explain why.
24. Why does flow decrease in your shower when someone flushes the toilet?
25. Plumbing usually includes air-filled tubes near water faucets, as shown in Figure. Explain why they are needed and how they work.
The vertical tube near the water tap remains full of air and serves a useful purpose.
12.5: The Onset of Turbulence
26. Doppler ultrasound can be used to measure the speed of blood in the body. If there is a partial constriction of an artery, where would you expect blood speed to be greatest, at or nearby the constriction? What are the two distinct causes of higher resistance in the constriction?
27. Sink drains often have a device such as that shown in Figure to help speed the flow of water. How does this work?
You will find devices such as this in many drains. They significantly increase flow rate.
28. Some ceiling fans have decorative wicker reeds on their blades. Discuss whether these fans are as quiet and efficient as those with smooth blades.
12.6: Motion of an Object in a Viscous Fluid
29. What direction will a helium balloon move inside a car that is slowing down—toward the front or back? Explain your answer.
30. Will identical raindrops fall more rapidly in 5º C air or 25º C air, neglecting any differences in air density? Explain your answer.
31. If you took two marbles of different sizes, what would you expect to observe about the relative magnitudes of their terminal velocities?
12.7: Molecular Transport Phenomena: Diffusion, Osmosis, and Related Processes
32. Why would you expect the rate of diffusion to increase with temperature? Can you give an example, such as the fact that you can dissolve sugar more rapidly in hot water?
33. How are osmosis and dialysis similar? How do they differ?
Problem & Exercises
12.1: Flow Rate and Its Relation to Velocity
34. What is the average flow rate in \(\displaystyle cm^3/s\) of gasoline to the engine of a car traveling at 100 km/h if it averages 10.0 km/L?
Solution
\(\displaystyle 2.78cm^3/s\)
35. The heart of a resting adult pumps blood at a rate of 5.00 L/min.
(a) Convert this to \(\displaystyle cm^3/s\).
(b) What is this rate in \(\displaystyle m^3/s\)?
36. Blood is pumped from the heart at a rate of 5.0 L/min into the aorta (of radius 1.0 cm). Determine the speed of blood through the aorta.
Solution
27 cm/s
37. Blood is flowing through an artery of radius 2 mm at a rate of 40 cm/s. Determine the flow rate and the volume that passes through the artery in a period of 30 s.
38. The Huka Falls on the Waikato River is one of New Zealand’s most visited natural tourist attractions (see Figure). On average the river has a flow rate of about 300,000 L/s. At the gorge, the river narrows to 20 m wide and averages 20 m deep.
(a) What is the average speed of the river in the gorge?
(b) What is the average speed of the water in the river downstream of the falls when it widens to 60 m and its depth increases to an average of 40 m?
The Huka Falls in Taupo, New Zealand, demonstrate flow rate. (credit: RaviGogna, Flickr
Solution
(a) 0.75 m/s
(b) 0.13 m/s
39. A major artery with a cross-sectional area of \(\displaystyle 1.00cm^2\) branches into 18 smaller arteries, each with an average cross-sectional area of \(\displaystyle 0.400cm^2\). By what factor is the average velocity of the blood reduced when it passes into these branches?
40. (a) As blood passes through the capillary bed in an organ, the capillaries join to form venules (small veins). If the blood speed increases by a factor of 4.00 and the total cross-sectional area of the venules is 10.0cm2, what is the total cross-sectional area of the capillaries feeding these venules?
(b) How many capillaries are involved if their average diameter is \(\displaystyle 10.0μm\)?
Solution
(a) \(\displaystyle 40.0cm^2\)
(b) \(\displaystyle 5.09×10^7\)
41. The human circulation system has approximately \(\displaystyle 1×10^9\) capillary vessels. Each vessel has a diameter of about 8μm. Assuming cardiac output is 5 L/min, determine the average velocity of blood flow through each capillary vessel.
42. (a) Estimate the time it would take to fill a private swimming pool with a capacity of 80,000 L using a garden hose delivering 60 L/min.
(b) How long would it take to fill if you could divert a moderate size river, flowing at \(\displaystyle 5000m^3/s\), into it?
Solution
(a) 22 h
(b) 0.016 s
43. The flow rate of blood through a \(\displaystyle 2.00×10^{–6}-m\) -radius capillary is \(\displaystyle 3.80×10^{-9}cm^3/s\).
(a) What is the speed of the blood flow? (This small speed allows time for diffusion of materials to and from the blood.)
(b) Assuming all the blood in the body passes through capillaries, how many of them must there be to carry a total flow of 90.0cm3/s? (The large number obtained is an overestimate, but it is still reasonable.)
44. (a) What is the fluid speed in a fire hose with a 9.00-cm diameter carrying 80.0 L of water per second? (b) What is the flow rate in cubic meters per second? (c) Would your answers be different if salt water replaced the fresh water in the fire hose?
Solution
(a) 12.6 m/s
(b) \(\displaystyle 0.0800m^3/s\)
(c) No, independent of density.
45. The main uptake air duct of a forced air gas heater is 0.300 m in diameter. What is the average speed of air in the duct if it carries a volume equal to that of the house’s interior every 15 min? The inside volume of the house is equivalent to a rectangular solid 13.0 m wide by 20.0 m long by 2.75 m high.
46. Water is moving at a velocity of 2.00 m/s through a hose with an internal diameter of 1.60 cm.
(a) What is the flow rate in liters per second?
(b) The fluid velocity in this hose’s nozzle is 15.0 m/s. What is the nozzle’s inside diameter?
Solution
(a) 0.402 L/s
(b) 0.584 cm
47. Prove that the speed of an incompressible fluid through a constriction, such as in a Venturi tube, increases by a factor equal to the square of the factor by which the diameter decreases. (The converse applies for flow out of a constriction into a larger-diameter region.)
48. Water emerges straight down from a faucet with a 1.80-cm diameter at a speed of 0.500 m/s. (Because of the construction of the faucet, there is no variation in speed across the stream.)
(a) What is the flow rate in \(\displaystyle cm^3/s\)?
(b) What is the diameter of the stream 0.200 m below the faucet? Neglect any effects due to surface tension.
Solution
(a) \(\displaystyle 127cm^3/s\)
(b) 0.890 cm
49. Unreasonable Results
A mountain stream is 10.0 m wide and averages 2.00 m in depth. During the spring runoff, the flow in the stream reaches \(\displaystyle 100,000m^3/s\).
(a) What is the average velocity of the stream under these conditions?
(b) What is unreasonable about this velocity?
(c) What is unreasonable or inconsistent about the premises?
12.2: Bernoulli’s Equation
50. Verify that pressure has units of energy per unit volume.
Solution
\(\displaystyle P=\frac{Force}{Area}\),
\(\displaystyle (P)_{units}=N/m^2=N⋅m/m^3=J/m^3\)
\(\displaystyle =energy/volume\)
51. Suppose you have a wind speed gauge like the pitot tube shown in [link](b). By what factor must wind speed increase to double the value of \(\displaystyle h\) in the manometer? Is this independent of the moving fluid and the fluid in the manometer?
52. If the pressure reading of your pitot tube is 15.0 mm Hg at a speed of 200 km/h, what will it be at 700 km/h at the same altitude?
Solution
184 mm Hg
53. Calculate the maximum height to which water could be squirted with the hose in [link] example if it: (a) Emerges from the nozzle. (b) Emerges with the nozzle removed, assuming the same flow rate.
54. Every few years, winds in Boulder, Colorado, attain sustained speeds of 45.0 m/s (about 100 mi/h) when the jet stream descends during early spring. Approximately what is the force due to the Bernoulli effect on a roof having an area of \(\displaystyle 220m^2\)? Typical air density in Boulder is \(\displaystyle 1.14kg/m^3\), and the corresponding atmospheric pressure is \(\displaystyle 8.89×10^4N/m^2\). (Bernoulli’s principle as stated in the text assumes laminar flow. Using the principle here produces only an approximate result, because there is significant turbulence.)
Solution
\(\displaystyle 2.54×10^5N\)
55. a) Calculate the approximate force on a square meter of sail, given the horizontal velocity of the wind is 6.00 m/s parallel to its front surface and 3.50 m/s along its back surface. Take the density of air to be \(\displaystyle 1.29 kg/m^3\). (The calculation, based on Bernoulli’s principle, is approximate due to the effects of turbulence.)
(b) Discuss whether this force is great enough to be effective for propelling a sailboat.
56. (a) What is the pressure drop due to the Bernoulli effect as water goes into a 3.00-cm-diameter nozzle from a 9.00-cm-diameter fire hose while carrying a flow of 40.0 L/s?
(b) To what maximum height above the nozzle can this water rise? (The actual height will be significantly smaller due to air resistance.)
Solution
(a) \(\displaystyle 1.58×10^6N/m^2\)
(b) 163 m
57. (a) Using Bernoulli’s equation, show that the measured fluid speed v for a pitot tube, like the one in Figure(b), is given by
\(\displaystyle v=(\frac{2ρ′gh}{ρ})^{1/2}\),
where \(\displaystyle h\) is the height of the manometer fluid, \(\displaystyle ρ′\) is the density of the manometer fluid, \(\displaystyle ρ\(\displaystyle is the density of the moving fluid, and \(\displaystyle g\(\displaystyle is the acceleration due to gravity. (Note that v is indeed proportional to the square root of \(\displaystyle h\), as stated in the text.)
(b) Calculate \(\displaystyle v\) for moving air if a mercury manometer’s \(\displaystyle h\) is 0.200 m.
12.3: The Most General Applications of Bernoulli’s Equation
58. Hoover Dam on the Colorado River is the highest dam in the United States at 221 m, with an output of 1300 MW. The dam generates electricity with water taken from a depth of 150 m and an average flow rate of \(\displaystyle 650m^3/s\).
(a) Calculate the power in this flow.
(b) What is the ratio of this power to the facility’s average of 680 MW?
Solution
(a) \(\displaystyle 9.56×10^8W\)
(b) 1.4
59. A frequently quoted rule of thumb in aircraft design is that wings should produce about 1000 N of lift per square meter of wing. (The fact that a wing has a top and bottom surface does not double its area.)
(a) At takeoff, an aircraft travels at 60.0 m/s, so that the air speed relative to the bottom of the wing is 60.0 m/s. Given the sea level density of air to be \(\displaystyle 1.29kg/m^3\), how fast must it move over the upper surface to create the ideal lift?
(b) How fast must air move over the upper surface at a cruising speed of 245 m/s and at an altitude where air density is one-fourth that at sea level? (Note that this is not all of the aircraft’s lift—some comes from the body of the plane, some from engine thrust, and so on. Furthermore, Bernoulli’s principle gives an approximate answer because flow over the wing creates turbulence.)
60. The left ventricle of a resting adult’s heart pumps blood at a flow rate of \(\displaystyle 83.0cm^3/s\), increasing its pressure by 110 mm Hg, its speed from zero to 30.0 cm/s, and its height by 5.00 cm. (All numbers are averaged over the entire heartbeat.) Calculate the total power output of the left ventricle. Note that most of the power is used to increase blood pressure.
Solution
1.26 W
61. A sump pump (used to drain water from the basement of houses built below the water table) is draining a flooded basement at the rate of 0.750 L/s, with an output pressure of \(\displaystyle 3.00×10^5N/m^2\).
(a) The water enters a hose with a 3.00-cm inside diameter and rises 2.50 m above the pump. What is its pressure at this point?
(b) The hose goes over the foundation wall, losing 0.500 m in height, and widens to 4.00 cm in diameter. What is the pressure now? You may neglect frictional losses in both parts of the problem.
12.4: Viscosity and Laminar Flow; Poiseuille’s Law
62. (a) Calculate the retarding force due to the viscosity of the air layer between a cart and a level air track given the following information—air temperature is 20º C , the cart is moving at 0.400 m/s, its surface area is \(\displaystyle 2.50×10^{−2}m^2\), and the thickness of the air layer is \(\displaystyle 6.00×10^{−5}m\).
(b) What is the ratio of this force to the weight of the 0.300-kg cart?
Solution
(a) \(\displaystyle 3.02×10^{−3}N\)
(b) \(\displaystyle 1.03×10^{−3}\)
63. What force is needed to pull one microscope slide over another at a speed of 1.00 cm/s, if there is a 0.500-mm-thick layer of 20º C water between them and the contact area is \(\displaystyle 8.00cm^2\)?
64. A glucose solution being administered with an IV has a flow rate of \(\displaystyle 4.00cm^3/min\). What will the new flow rate be if the glucose is replaced by whole blood having the same density but a viscosity 2.50 times that of the glucose? All other factors remain constant.
Solution
\(\displaystyle 1.60 cm^3/min\)
65. The pressure drop along a length of artery is 100 Pa, the radius is 10 mm, and the flow is laminar. The average speed of the blood is 15 mm/s.
(a) What is the net force on the blood in this section of artery?
(b) What is the power expended maintaining the flow?
66. A small artery has a length of \(\displaystyle 1.1×10^{−3}m\) and a radius of \(\displaystyle 2.5×10^{−5}m\). If the pressure drop across the artery is 1.3 kPa, what is the flow rate through the artery? (Assume that the temperature is 37º C.)
Solution
\(\displaystyle 8.7×10^{−11}m^3/s\)
67. Fluid originally flows through a tube at a rate of \(\displaystyle 100cm^3/s\). To illustrate the sensitivity of flow rate to various factors, calculate the new flow rate for the following changes with all other factors remaining the same as in the original conditions.
(a) Pressure difference increases by a factor of 1.50.
(b) A new fluid with 3.00 times greater viscosity is substituted.
(c) The tube is replaced by one having 4.00 times the length.
(d) Another tube is used with a radius 0.100 times the original.
(e) Yet another tube is substituted with a radius 0.100 times the original and half the length, and the pressure difference is increased by a factor of 1.50.
68. The arterioles (small arteries) leading to an organ, constrict in order to decrease flow to the organ. To shut down an organ, blood flow is reduced naturally to 1.00% of its original value. By what factor did the radii of the arterioles constrict? Penguins do this when they stand on ice to reduce the blood flow to their feet.
Solution
0.316
69. Angioplasty is a technique in which arteries partially blocked with plaque are dilated to increase blood flow. By what factor must the radius of an artery be increased in order to increase blood flow by a factor of 10?
70. (a) Suppose a blood vessel’s radius is decreased to 90.0% of its original value by plaque deposits and the body compensates by increasing the pressure difference along the vessel to keep the flow rate constant. By what factor must the pressure difference increase?
(b) If turbulence is created by the obstruction, what additional effect would it have on the flow rate?
Solution
(a) 1.52
(b) Turbulence will decrease the flow rate of the blood, which would require an even larger increase in the pressure difference, leading to higher blood pressure.
71. A spherical particle falling at a terminal speed in a liquid must have the gravitational force balanced by the drag force and the buoyant force. The buoyant force is equal to the weight of the displaced fluid, while the drag force is assumed to be given by Stokes Law, \(\displaystyle F_s=6πrηv\). Show that the terminal speed is given by
\(\displaystyle v=\frac{2R^2g}{9η}(ρ_s−ρ_1),\)
where \(\displaystyle R\) is the radius of the sphere, \(\displaystyle ρ_s\) is its density, and \(\displaystyle ρ_1\) is the density of the fluid and \(\displaystyle η\) the coefficient of viscosity.
72. Using the equation of the previous problem, find the viscosity of motor oil in which a steel ball of radius 0.8 mm falls with a terminal speed of 4.32 cm/s. The densities of the ball and the oil are 7.86 and 0.88 g/mL, respectively.
Solution
\(\displaystyle 225mPa⋅s\)
73. A skydiver will reach a terminal velocity when the air drag equals their weight. For a skydiver with high speed and a large body, turbulence is a factor. The drag force then is approximately proportional to the square of the velocity. Taking the drag force to be \(\displaystyle F_D=\frac{1}{2}ρAv^2\) and setting this equal to the person’s weight, find the terminal speed for a person falling “spread eagle.” Find both a formula and a number for \(\displaystyle v_t\), with assumptions as to size.
74. A layer of oil 1.50 mm thick is placed between two microscope slides. Researchers find that a force of \(\displaystyle 5.50×10^{−4}N\) is required to glide one over the other at a speed of 1.00 cm/s when their contact area is \(\displaystyle 6.00cm^2\). What is the oil’s viscosity? What type of oil might it be?
Solution
\(\displaystyle 0.138 Pa⋅s\) or Olive oil.
75. (a) Verify that a 19.0% decrease in laminar flow through a tube is caused by a 5.00% decrease in radius, assuming that all other factors remain constant, as stated in the text.
(b) What increase in flow is obtained from a 5.00% increase in radius, again assuming all other factors remain constant?
76. Example dealt with the flow of saline solution in an IV system.
(a) Verify that a pressure of \(\displaystyle 1.62×10^4N/m^2\) is created at a depth of 1.61 m in a saline solution, assuming its density to be that of sea water.
(b) Calculate the new flow rate if the height of the saline solution is decreased to 1.50 m.
(c) At what height would the direction of flow be reversed? (This reversal can be a problem when patients stand up.)
Solution
(a) \(\displaystyle 1.62×10^4N/m^2\)
(b) \(\displaystyle 0.111 cm^3/s\)
(c)10.6 cm
77. When physicians diagnose arterial blockages, they quote the reduction in flow rate. If the flow rate in an artery has been reduced to 10.0% of its normal value by a blood clot and the average pressure difference has increased by 20.0%, by what factor has the clot reduced the radius of the artery?
78. During a marathon race, a runner’s blood flow increases to 10.0 times her resting rate. Her blood’s viscosity has dropped to 95.0% of its normal value, and the blood pressure difference across the circulatory system has increased by 50.0%. By what factor has the average radii of her blood vessels increased?
Solution
1.59
79. Water supplied to a house by a water main has a pressure of \(\displaystyle 3.00×10^5N/m^2\) early on a summer day when neighborhood use is low. This pressure produces a flow of 20.0 L/min through a garden hose. Later in the day, pressure at the exit of the water main and entrance to the house drops, and a flow of only 8.00 L/min is obtained through the same hose.
(a) What pressure is now being supplied to the house, assuming resistance is constant?
(b) By what factor did the flow rate in the water main increase in order to cause this decrease in delivered pressure? The pressure at the entrance of the water main is \(\displaystyle 5.00×10^5N/m^2\), and the original flow rate was 200 L/min.
(c) How many more users are there, assuming each would consume 20.0 L/min in the morning?
80. An oil gusher shoots crude oil 25.0 m into the air through a pipe with a 0.100-m diameter. Neglecting air resistance but not the resistance of the pipe, and assuming laminar flow, calculate the gauge pressure at the entrance of the 50.0-m-long vertical pipe. Take the density of the oil to be \(\displaystyle 900kg/m^3\) and its viscosity to be \(\displaystyle 1.00(N/m^2)⋅s\) (or \(\displaystyle 1.00Pa⋅s\)). Note that you must take into account the pressure due to the 50.0-m column of oil in the pipe.
Solution
\(\displaystyle 2.95×10^6N/m^2\)(gauge pressure)
81. Concrete is pumped from a cement mixer to the place it is being laid, instead of being carried in wheelbarrows. The flow rate is 200.0 L/min through a 50.0-m-long, 8.00-cm-diameter hose, and the pressure at the pump is \(\displaystyle 8.00×10^6N/m^2\).
(a) Calculate the resistance of the hose.
(b) What is the viscosity of the concrete, assuming the flow is laminar?
(c) How much power is being supplied, assuming the point of use is at the same level as the pump? You may neglect the power supplied to increase the concrete’s velocity.
82. Construct Your Own Problem
Consider a coronary artery constricted by arteriosclerosis. Construct a problem in which you calculate the amount by which the diameter of the artery is decreased, based on an assessment of the decrease in flow rate.
83. Consider a river that spreads out in a delta region on its way to the sea. Construct a problem in which you calculate the average speed at which water moves in the delta region, based on the speed at which it was moving up river. Among the things to consider are the size and flow rate of the river before it spreads out and its size once it has spread out. You can construct the problem for the river spreading out into one large river or into multiple smaller rivers.
12.5: The Onset of Turbulence
84. Verify that the flow of oil is laminar (barely) for an oil gusher that shoots crude oil 25.0 m into the air through a pipe with a 0.100-m diameter. The vertical pipe is 50 m long. Take the density of the oil to be \(\displaystyle 900 kg/m^3\) and its viscosity to be \(\displaystyle 1.00(N/m^2)⋅s\) (or \(\displaystyle 1.00 Pa⋅s\)).
Solution
\(\displaystyle N_R=1.99×10^2< 2000\)
85. Show that the Reynolds number \(\displaystyle N_R\) is unitless by substituting units for all the quantities in its definition and cancelling.
86. Calculate the Reynolds numbers for the flow of water through
(a) a nozzle with a radius of 0.250 cm and
(b) a garden hose with a radius of 0.900 cm, when the nozzle is attached to the hose. The flow rate through hose and nozzle is 0.500 L/s. Can the flow in either possibly be laminar?
Solution
(a) nozzle: \(\displaystyle 1.27×10^5\), not laminar
(b) hose: \(\displaystyle 3.51×10^4\), not laminar.
87.  The hose goes 10.0 m up a ladder to a nozzle having an inside diameter of 3.00 cm. Calculate the Reynolds numbers for flow in the fire hose and nozzle to show that the flow in each must be turbulent.
88. Concrete is pumped from a cement mixer to the place it is being laid, instead of being carried in wheelbarrows. The flow rate is 200.0 L/min through a 50.0-m-long, 8.00-cm-diameter hose, and the pressure at the pump is \(\displaystyle 8.00×10^6N/m^2\). Verify that the flow of concrete is laminar taking concrete’s viscosity to be \(\displaystyle 48.0(N/m^2)⋅s\), and given its density is \(\displaystyle 2300 kg/m^3\).
Solution
2.54 << 2000, laminar.
89. At what flow rate might turbulence begin to develop in a water main with a 0.200-m diameter? Assume a \(\displaystyle 20º C\) temperature.
90. What is the greatest average speed of blood flow at \(\displaystyle 37º C\) in an artery of radius 2.00 mm if the flow is to remain laminar? What is the corresponding flow rate? Take the density of blood to be \(\displaystyle 1025 kg/m^3\).
Solution
1.02 m/s
\(\displaystyle 1.28×10^{–2}L/s\)
91. In Take-Home Experiment: Inhalation, we measured the average flow rate \(\displaystyle Q\) of air traveling through the trachea during each inhalation. Now calculate the average air speed in meters per second through your trachea during each inhalation. The radius of the trachea in adult humans is approximately \(\displaystyle 10^{−2}m\). From the data above, calculate the Reynolds number for the air flow in the trachea during inhalation. Do you expect the air flow to be laminar or turbulent?
92. Gasoline is piped underground from refineries to major users. The flow rate is \(\displaystyle 3.00×10^{–2}m^3/s\) (about 500 gal/min), the viscosity of gasoline is \(\displaystyle 1.00×10^{–3}(N/m^2)⋅s\), and its density is \(\displaystyle 680kg/m^3\).
(a) What minimum diameter must the pipe have if the Reynolds number is to be less than 2000?
(b) What pressure difference must be maintained along each kilometer of the pipe to maintain this flow rate?
Solution
(a) \(\displaystyle ≥ 13.0 m\)
(b) \(\displaystyle 2.68×10^{−6}N/m^2\)
93. Assuming that blood is an ideal fluid, calculate the critical flow rate at which turbulence is a certainty in the aorta. Take the diameter of the aorta to be 2.50 cm. (Turbulence will actually occur at lower average flow rates, because blood is not an ideal fluid. Furthermore, since blood flow pulses, turbulence may occur during only the high-velocity part of each heartbeat.)
94. Unreasonable Results
A fairly large garden hose has an internal radius of 0.600 cm and a length of 23.0 m. The nozzleless horizontal hose is attached to a faucet, and it delivers 50.0 L/s.
(a) What water pressure is supplied by the faucet?
(b) What is unreasonable about this pressure?
(c) What is unreasonable about the premise?
(d) What is the Reynolds number for the given flow? (Take the viscosity of water as \(\displaystyle 1.005×10^{–3}(N/m^2)⋅s\).)
Solution
(a) 23.7 atm or \(\displaystyle 344 lb/in^2\)
(b) The pressure is much too high.
(c) The assumed flow rate is very high for a garden hose.
(d) \(\displaystyle 5.27×10^6 > > 3000\), turbulent, contrary to the assumption of laminar flow when using this equation.
12.7: Molecular Transport Phenomena: Diffusion, Osmosis, and Related Processes
95. You can smell perfume very shortly after opening the bottle. To show that it is not reaching your nose by diffusion, calculate the average distance a perfume molecule moves in one second in air, given its diffusion constant \(\displaystyle D\) to be \(\displaystyle 1.00×10^{–6}m^2/s\).
Solution
\(\displaystyle 1.41×10^{−3}m\)
96. What is the ratio of the average distances that oxygen will diffuse in a given time in air and water? Why is this distance less in water (equivalently, why is \(\displaystyle D\) less in water)?
97. Oxygen reaches the veinless cornea of the eye by diffusing through its tear layer, which is 0.500-mm thick. How long does it take the average oxygen molecule to do this?
Solution
\(\displaystyle 1.3×10^2s\)
98. (a) Find the average time required for an oxygen molecule to diffuse through a 0.200-mm-thick tear layer on the cornea.
(b) How much time is required to diffuse \(\displaystyle 0.500cm^3\) of oxygen to the cornea if its surface area is \(\displaystyle 1.00cm^2\)?
99. Suppose hydrogen and oxygen are diffusing through air. A small amount of each is released simultaneously. How much time passes before the hydrogen is 1.00 s ahead of the oxygen? Such differences in arrival times are used as an analytical tool in gas chromatography.
Solution
0.391 s
Contributors and Attributions
-
Paul Peter Urone (Professor Emeritus at California State University, Sacramento) and Roger Hinrichs (State University of New York, College at Oswego) with Contributing Authors: Kim Dirks (University of Auckland) and Manjula Sharma (University of Sydney). This work is licensed by OpenStax University Physics under a Creative Commons Attribution License (by 4.0) .


8.5: Firm Vision and Mission
- What is the difference between a firm’s vision and its mission?
The first step in the process of developing a successful strategic position should be part of the founding of the firm itself. When entrepreneurs decide to start a business, they usually have a reason for starting it, a reason that answers the question “What is the point of this business?” Even if an entrepreneur initially thinks of starting a business in order to be their own boss, they must also have an idea about what their business will do. Overall, entrepreneurs start businesses for a variety of reasons. A vision statement is an expression of what a business’s founders want that business to accomplish. The vision statement is usually very broad, and it does not even have to mention a product or service. The vision statement does not describe the strategy a firm will use to follow its vision—it is simply a sentence or two that states why the business exists.
While a firm’s vision statement is a general statement about its values, a firm’s mission statement is more specific. The mission statement takes the why of a vision statement and gives a broad description of how the firm will try to make its vision a reality. A mission statement is still not exactly a strategy, but it focuses on describing the products a firm plans to offer or the target markets it plans to serve.
Exhibit 8.4 gives examples of vision and mission statements for the Walt Disney Company and for Ikea. Notice that in both cases, the vision statement is very broad and is not something a business could use as a strategy because there’s simply not enough information to show what kind of business they might be. The mission statements, on the other hand, describe the products and services each company plans to offer and the customers each company plans to serve to fulfill their vision.
Exhibit 8.4 Vision and Mission Statements (Attribution: Copyright Rice University, OpenStax, under CC-BY 4.0 license)
What's interesting about vision and mission statements is that many companies confuse them, calling a very broad statement their mission. For example, Microsoft says that its mission is “to help people around the world realize their full potential.” 4 By the description above, this would be a good vision statement. However, Microsoft’s official vision statement is to “empower people through great software anytime, anyplace, and on any device” (The Marketing Blender, 2017). Although the second statement is also quite broad, it does say how Microsoft wants to achieve the first statement, which makes it a better mission statement than vision statement.
Why are vision and mission statements important to a firm’s strategy for developing a competitive advantage? To put it simply, you can’t make a plan or strategy unless you know what you want to accomplish. Vision and mission statements together are the first building blocks in defining why a firm exists and in developing a plan to accomplish what the firm wants to accomplish.
- What does a mission statement explain about a firm that a vision statement does not?
- What are the similarities and differences between vision and mission?