index
int64 0
21k
| title
stringclasses 490
values | context
stringlengths 151
4.06k
| x
float32 -1
1
| y
float32 -1
1
| tile_index_64
int64 25
4.07k
| tile_index_128
int64 51
16.3k
| cluster
int64 0
216
| raw_cluster
int64 -1
216
| label
stringclasses 217
values | deleted
bool 1
class |
|---|---|---|---|---|---|---|---|---|---|---|
20,900 | French_and_Indian_War | Governor Vaudreuil, who harboured ambitions to become the French commander in chief (in addition to his role as governor), acted during the winter of 1756 before those reinforcements arrived. Scouts had reported the weakness of the British supply chain, so he ordered an attack against the forts Shirley had erected at the Oneida Carry. In the March Battle of Fort Bull, French forces destroyed the fort and large quantities of supplies, including 45,000 pounds of gunpowder. They set back any British hopes for campaigns on Lake Ontario, and endangered the Oswego garrison, already short on supplies. French forces in the Ohio valley also continued to intrigue with Indians throughout the area, encouraging them to raid frontier settlements. This led to ongoing alarms along the western frontiers, with streams of refugees returning east to get away from the action. | 0.269991 | -0.265997 | 1,512 | 5,969 | 213 | 213 | Canadian Historical Conflicts | false |
20,901 | French_and_Indian_War | The new British command was not in place until July. When he arrived in Albany, Abercrombie refused to take any significant actions until Loudoun approved them. Montcalm took bold action against his inertia. Building on Vaudreuil's work harassing the Oswego garrison, Montcalm executed a strategic feint by moving his headquarters to Ticonderoga, as if to presage another attack along Lake George. With Abercrombie pinned down at Albany, Montcalm slipped away and led the successful attack on Oswego in August. In the aftermath, Montcalm and the Indians under his command disagreed about the disposition of prisoners' personal effects. The Europeans did not consider them prizes and prevented the Indians from stripping the prisoners of their valuables, which angered the Indians. | 0.283782 | -0.268914 | 1,513 | 5,970 | 213 | 213 | Canadian Historical Conflicts | false |
20,902 | French_and_Indian_War | Loudoun, a capable administrator but a cautious field commander, planned one major operation for 1757: an attack on New France's capital, Quebec. Leaving a sizable force at Fort William Henry to distract Montcalm, he began organizing for the expedition to Quebec. He was then ordered by William Pitt, the Secretary of State responsible for the colonies, to attack Louisbourg first. Beset by delays of all kinds, the expedition was finally ready to sail from Halifax, Nova Scotia in early August. In the meantime French ships had escaped the British blockade of the French coast, and a fleet outnumbering the British one awaited Loudoun at Louisbourg. Faced with this strength, Loudoun returned to New York amid news that a massacre had occurred at Fort William Henry. | 0.268161 | -0.273445 | 1,512 | 5,969 | 213 | 213 | Canadian Historical Conflicts | false |
20,903 | French_and_Indian_War | French irregular forces (Canadian scouts and Indians) harassed Fort William Henry throughout the first half of 1757. In January they ambushed British rangers near Ticonderoga. In February they launched a daring raid against the position across the frozen Lake George, destroying storehouses and buildings outside the main fortification. In early August, Montcalm and 7,000 troops besieged the fort, which capitulated with an agreement to withdraw under parole. When the withdrawal began, some of Montcalm's Indian allies, angered at the lost opportunity for loot, attacked the British column, killing and capturing several hundred men, women, children, and slaves. The aftermath of the siege may have contributed to the transmission of smallpox into remote Indian populations; as some Indians were reported to have traveled from beyond the Mississippi to participate in the campaign and returned afterward having been exposed to European carriers. | 0.270685 | -0.266662 | 1,512 | 5,969 | 213 | 213 | Canadian Historical Conflicts | false |
20,904 | French_and_Indian_War | Vaudreuil and Montcalm were minimally resupplied in 1758, as the British blockade of the French coastline limited French shipping. The situation in New France was further exacerbated by a poor harvest in 1757, a difficult winter, and the allegedly corrupt machinations of François Bigot, the intendant of the territory. His schemes to supply the colony inflated prices and were believed by Montcalm to line his pockets and those of his associates. A massive outbreak of smallpox among western tribes led many of them to stay away from trading in 1758. While many parties to the conflict blamed others (the Indians blamed the French for bringing "bad medicine" as well as denying them prizes at Fort William Henry), the disease was probably spread through the crowded conditions at William Henry after the battle. Montcalm focused his meager resources on the defense of the St. Lawrence, with primary defenses at Carillon, Quebec, and Louisbourg, while Vaudreuil argued unsuccessfully for a continuation of the raiding tactics that had worked quite effectively in previous years. | 0.274506 | -0.264195 | 1,512 | 6,097 | 213 | 213 | Canadian Historical Conflicts | false |
20,905 | French_and_Indian_War | The British failures in North America, combined with other failures in the European theater, led to the fall from power of Newcastle and his principal military advisor, the Duke of Cumberland. Newcastle and Pitt joined in an uneasy coalition in which Pitt dominated the military planning. He embarked on a plan for the 1758 campaign that was largely developed by Loudoun. He had been replaced by Abercrombie as commander in chief after the failures of 1757. Pitt's plan called for three major offensive actions involving large numbers of regular troops, supported by the provincial militias, aimed at capturing the heartlands of New France. Two of the expeditions were successful, with Fort Duquesne and Louisbourg falling to sizable British forces. | 0.282047 | -0.267457 | 1,513 | 5,970 | 213 | 213 | Canadian Historical Conflicts | false |
20,906 | French_and_Indian_War | The third invasion was stopped with the improbable French victory in the Battle of Carillon, in which 3,600 Frenchmen famously and decisively defeated Abercrombie's force of 18,000 regulars, militia and Native American allies outside the fort the French called Carillon and the British called Ticonderoga. Abercrombie saved something from the disaster when he sent John Bradstreet on an expedition that successfully destroyed Fort Frontenac, including caches of supplies destined for New France's western forts and furs destined for Europe. Abercrombie was recalled and replaced by Jeffery Amherst, victor at Louisbourg. | 0.285719 | -0.263712 | 1,513 | 6,098 | 213 | 213 | Canadian Historical Conflicts | false |
20,907 | French_and_Indian_War | In the aftermath of generally poor French results in most theaters of the Seven Years' War in 1758, France's new foreign minister, the duc de Choiseul, decided to focus on an invasion of Britain, to draw British resources away from North America and the European mainland. The invasion failed both militarily and politically, as Pitt again planned significant campaigns against New France, and sent funds to Britain's ally on the mainland, Prussia, and the French Navy failed in the 1759 naval battles at Lagos and Quiberon Bay. In one piece of good fortune, some French supply ships managed to depart France, eluding the British blockade of the French coast. | 0.311654 | -0.274269 | 1,513 | 5,971 | 213 | -1 | Canadian Historical Conflicts | false |
20,908 | French_and_Indian_War | British victories continued in all theaters in the Annus Mirabilis of 1759, when they finally captured Ticonderoga, James Wolfe defeated Montcalm at Quebec (in a battle that claimed the lives of both commanders), and victory at Fort Niagara successfully cut off the French frontier forts further to the west and south. The victory was made complete in 1760 when, despite losing outside Quebec City in the Battle of Sainte-Foy, the British were able to prevent the arrival of French relief ships in the naval Battle of the Restigouche while armies marched on Montreal from three sides. | 0.277787 | -0.260396 | 1,512 | 6,097 | 213 | 213 | Canadian Historical Conflicts | false |
20,909 | French_and_Indian_War | In September 1760, and before any hostilities erupted, Governor Vaudreuil negotiated from Montreal a capitulation with General Amherst. Amherst granted Vaudreuil's request that any French residents who chose to remain in the colony would be given freedom to continue worshiping in their Roman Catholic tradition, continued ownership of their property, and the right to remain undisturbed in their homes. The British provided medical treatment for the sick and wounded French soldiers and French regular troops were returned to France aboard British ships with an agreement that they were not to serve again in the present war. | 0.276447 | -0.264714 | 1,512 | 6,097 | 213 | 213 | Canadian Historical Conflicts | false |
20,910 | French_and_Indian_War | The war in North America officially ended with the signing of the Treaty of Paris on 10 February 1763, and war in the European theatre of the Seven Years' War was settled by the Treaty of Hubertusburg on 15 February 1763. The British offered France the choice of surrendering either its continental North American possessions east of the Mississippi or the Caribbean islands of Guadeloupe and Martinique, which had been occupied by the British. France chose to cede the former, but was able to negotiate the retention of Saint Pierre and Miquelon, two small islands in the Gulf of St. Lawrence, along with fishing rights in the area. They viewed the economic value of the Caribbean islands' sugar cane to be greater and easier to defend than the furs from the continent. The contemporaneous French philosopher Voltaire referred to Canada disparagingly as nothing more than a few acres of snow. The British, for their part, were happy to take New France, as defence of their North American colonies would no longer be an issue and also because they already had ample places from which to obtain sugar. Spain, which traded Florida to Britain to regain Cuba, also gained Louisiana, including New Orleans, from France in compensation for its losses. Great Britain and Spain also agreed that navigation on the Mississippi River was to be open to vessels of all nations. | 0.283637 | -0.246036 | 1,577 | 6,226 | 213 | -1 | Canadian Historical Conflicts | false |
20,911 | French_and_Indian_War | Britain gained control of French Canada and Acadia, colonies containing approximately 80,000 primarily French-speaking Roman Catholic residents. The deportation of Acadians beginning in 1755 resulted in land made available to migrants from Europe and the colonies further south. The British resettled many Acadians throughout its North American provinces, but many went to France, and some went to New Orleans, which they had expected to remain French. Some were sent to colonize places as diverse as French Guiana and the Falkland Islands; these latter efforts were unsuccessful. Others migrated to places like Saint-Domingue, and fled to New Orleans after the Haitian Revolution. The Louisiana population contributed to the founding of the modern Cajun population. (The French word "Acadien" evolved to "Cadien", then to "Cajun".) | 0.253903 | -0.25438 | 1,512 | 6,096 | 213 | 213 | Canadian Historical Conflicts | false |
20,912 | French_and_Indian_War | Following the treaty, King George III issued the Royal Proclamation of 1763 on October 7, 1763, which outlined the division and administration of the newly conquered territory, and to some extent continues to govern relations between the government of modern Canada and the First Nations. Included in its provisions was the reservation of lands west of the Appalachian Mountains to its Indian population, a demarcation that was at best a temporary impediment to a rising tide of westward-bound settlers. The proclamation also contained provisions that prevented civic participation by the Roman Catholic Canadians. When accommodations were made in the Quebec Act in 1774 to address this and other issues, religious concerns were raised in the largely Protestant Thirteen Colonies over the advance of "popery"; the Act maintained French Civil law, including the seigneurial system, a medieval code soon to be removed from France within a generation by the French Revolution. | 0.26492 | -0.278049 | 1,512 | 5,968 | 213 | -1 | Canadian Historical Conflicts | false |
20,913 | French_and_Indian_War | For many native populations, the elimination of French power in North America meant the disappearance of a strong ally and counterweight to British expansion, leading to their ultimate dispossession. The Ohio Country was particularly vulnerable to legal and illegal settlement due to the construction of military roads to the area by Braddock and Forbes. Although the Spanish takeover of the Louisiana territory (which was not completed until 1769) had modest repercussions, the British takeover of Spanish Florida resulted in the westward migration of tribes that did not want to do business with the British, and a rise in tensions between the Choctaw and the Creek, historic enemies whose divisions the British at times exploited. The change of control in Florida also prompted most of its Spanish Catholic population to leave. Most went to Cuba, including the entire governmental records from St. Augustine, although some Christianized Yamasee were resettled to the coast of Mexico. | 0.197868 | -0.219583 | 1,574 | 6,348 | 212 | 212 | Caribbean and Colonial History | false |
20,914 | Force | Philosophers in antiquity used the concept of force in the study of stationary and moving objects and simple machines, but thinkers such as Aristotle and Archimedes retained fundamental errors in understanding force. In part this was due to an incomplete understanding of the sometimes non-obvious force of friction, and a consequently inadequate view of the nature of natural motion. A fundamental error was the belief that a force is required to maintain motion, even at a constant velocity. Most of the previous misunderstandings about motion and force were eventually corrected by Galileo Galilei and Sir Isaac Newton. With his mathematical insight, Sir Isaac Newton formulated laws of motion that were not improved-on for nearly three hundred years. By the early 20th century, Einstein developed a theory of relativity that correctly predicted the action of forces on objects with increasing momenta near the speed of light, and also provided insight into the forces produced by gravitation and inertia. | 0.028262 | 0.647787 | 3,360 | 13,505 | 87 | 87 | Energy and Physics Concepts | false |
20,915 | Force | With modern insights into quantum mechanics and technology that can accelerate particles close to the speed of light, particle physics has devised a Standard Model to describe forces between particles smaller than atoms. The Standard Model predicts that exchanged particles called gauge bosons are the fundamental means by which forces are emitted and absorbed. Only four main interactions are known: in order of decreasing strength, they are: strong, electromagnetic, weak, and gravitational.:2–10:79 High-energy particle physics observations made during the 1970s and 1980s confirmed that the weak and electromagnetic forces are expressions of a more fundamental electroweak interaction. | 0.005033 | 0.664486 | 3,424 | 13,632 | 87 | 87 | Energy and Physics Concepts | false |
20,916 | Force | Aristotle provided a philosophical discussion of the concept of a force as an integral part of Aristotelian cosmology. In Aristotle's view, the terrestrial sphere contained four elements that come to rest at different "natural places" therein. Aristotle believed that motionless objects on Earth, those composed mostly of the elements earth and water, to be in their natural place on the ground and that they will stay that way if left alone. He distinguished between the innate tendency of objects to find their "natural place" (e.g., for heavy bodies to fall), which led to "natural motion", and unnatural or forced motion, which required continued application of a force. This theory, based on the everyday experience of how objects move, such as the constant application of a force needed to keep a cart moving, had conceptual trouble accounting for the behavior of projectiles, such as the flight of arrows. The place where the archer moves the projectile was at the start of the flight, and while the projectile sailed through the air, no discernible efficient cause acts on it. Aristotle was aware of this problem and proposed that the air displaced through the projectile's path carries the projectile to its target. This explanation demands a continuum like air for change of place in general. | 0.541305 | 0.505474 | 3,121 | 12,386 | 151 | -1 | Philosophical Ideals and Challenges | false |
20,917 | Force | The shortcomings of Aristotelian physics would not be fully corrected until the 17th century work of Galileo Galilei, who was influenced by the late Medieval idea that objects in forced motion carried an innate force of impetus. Galileo constructed an experiment in which stones and cannonballs were both rolled down an incline to disprove the Aristotelian theory of motion early in the 17th century. He showed that the bodies were accelerated by gravity to an extent that was independent of their mass and argued that objects retain their velocity unless acted on by a force, for example friction. | 0.040437 | 0.639013 | 3,361 | 13,378 | 87 | 87 | Energy and Physics Concepts | false |
20,918 | Force | Newton's First Law of Motion states that objects continue to move in a state of constant velocity unless acted upon by an external net force or resultant force. This law is an extension of Galileo's insight that constant velocity was associated with a lack of net force (see a more detailed description of this below). Newton proposed that every object with mass has an innate inertia that functions as the fundamental equilibrium "natural state" in place of the Aristotelian idea of the "natural state of rest". That is, the first law contradicts the intuitive Aristotelian belief that a net force is required to keep an object moving with constant velocity. By making rest physically indistinguishable from non-zero constant velocity, Newton's First Law directly connects inertia with the concept of relative velocities. Specifically, in systems where objects are moving with different velocities, it is impossible to determine which object is "in motion" and which object is "at rest". In other words, to phrase matters more technically, the laws of physics are the same in every inertial frame of reference, that is, in all frames related by a Galilean transformation. | 0.02756 | 0.662115 | 3,424 | 13,633 | 87 | -1 | Energy and Physics Concepts | false |
20,919 | Force | For instance, while traveling in a moving vehicle at a constant velocity, the laws of physics do not change from being at rest. A person can throw a ball straight up in the air and catch it as it falls down without worrying about applying a force in the direction the vehicle is moving. This is true even though another person who is observing the moving vehicle pass by also observes the ball follow a curving parabolic path in the same direction as the motion of the vehicle. It is the inertia of the ball associated with its constant velocity in the direction of the vehicle's motion that ensures the ball continues to move forward even as it is thrown up and falls back down. From the perspective of the person in the car, the vehicle and everything inside of it is at rest: It is the outside world that is moving with a constant speed in the opposite direction. Since there is no experiment that can distinguish whether it is the vehicle that is at rest or the outside world that is at rest, the two situations are considered to be physically indistinguishable. Inertia therefore applies equally well to constant velocity motion as it does to rest. | 0.036346 | 0.644482 | 3,361 | 13,506 | 87 | 87 | Energy and Physics Concepts | false |
20,920 | Force | The concept of inertia can be further generalized to explain the tendency of objects to continue in many different forms of constant motion, even those that are not strictly constant velocity. The rotational inertia of planet Earth is what fixes the constancy of the length of a day and the length of a year. Albert Einstein extended the principle of inertia further when he explained that reference frames subject to constant acceleration, such as those free-falling toward a gravitating object, were physically equivalent to inertial reference frames. This is why, for example, astronauts experience weightlessness when in free-fall orbit around the Earth, and why Newton's Laws of Motion are more easily discernible in such environments. If an astronaut places an object with mass in mid-air next to himself, it will remain stationary with respect to the astronaut due to its inertia. This is the same thing that would occur if the astronaut and the object were in intergalactic space with no net force of gravity acting on their shared reference frame. This principle of equivalence was one of the foundational underpinnings for the development of the general theory of relativity. | 0.036554 | 0.64184 | 3,361 | 13,506 | 87 | 87 | Energy and Physics Concepts | false |
20,921 | Force | Newton's Second Law asserts the direct proportionality of acceleration to force and the inverse proportionality of acceleration to mass. Accelerations can be defined through kinematic measurements. However, while kinematics are well-described through reference frame analysis in advanced physics, there are still deep questions that remain as to what is the proper definition of mass. General relativity offers an equivalence between space-time and mass, but lacking a coherent theory of quantum gravity, it is unclear as to how or whether this connection is relevant on microscales. With some justification, Newton's second law can be taken as a quantitative definition of mass by writing the law as an equality; the relative units of force and mass then are fixed. | 0.018217 | 0.659385 | 3,424 | 13,633 | 87 | 87 | Energy and Physics Concepts | false |
20,922 | Force | Newton's Third Law is a result of applying symmetry to situations where forces can be attributed to the presence of different objects. The third law means that all forces are interactions between different bodies,[Note 3] and thus that there is no such thing as a unidirectional force or a force that acts on only one body. Whenever a first body exerts a force F on a second body, the second body exerts a force −F on the first body. F and −F are equal in magnitude and opposite in direction. This law is sometimes referred to as the action-reaction law, with F called the "action" and −F the "reaction". The action and the reaction are simultaneous: | 0.01036 | 0.655137 | 3,360 | 13,504 | 87 | 87 | Energy and Physics Concepts | false |
20,923 | Force | This means that in a closed system of particles, there are no internal forces that are unbalanced. That is, the action-reaction force shared between any two objects in a closed system will not cause the center of mass of the system to accelerate. The constituent objects only accelerate with respect to each other, the system itself remains unaccelerated. Alternatively, if an external force acts on the system, then the center of mass will experience an acceleration proportional to the magnitude of the external force divided by the mass of the system.:19-1 | 0.022257 | 0.661856 | 3,424 | 13,633 | 87 | 87 | Energy and Physics Concepts | false |
20,924 | Force | Since forces are perceived as pushes or pulls, this can provide an intuitive understanding for describing forces. As with other physical concepts (e.g. temperature), the intuitive understanding of forces is quantified using precise operational definitions that are consistent with direct observations and compared to a standard measurement scale. Through experimentation, it is determined that laboratory measurements of forces are fully consistent with the conceptual definition of force offered by Newtonian mechanics. | 0.009967 | 0.655249 | 3,360 | 13,504 | 87 | 87 | Energy and Physics Concepts | false |
20,925 | Force | Forces act in a particular direction and have sizes dependent upon how strong the push or pull is. Because of these characteristics, forces are classified as "vector quantities". This means that forces follow a different set of mathematical rules than physical quantities that do not have direction (denoted scalar quantities). For example, when determining what happens when two forces act on the same object, it is necessary to know both the magnitude and the direction of both forces to calculate the result. If both of these pieces of information are not known for each force, the situation is ambiguous. For example, if you know that two people are pulling on the same rope with known magnitudes of force but you do not know which direction either person is pulling, it is impossible to determine what the acceleration of the rope will be. The two people could be pulling against each other as in tug of war or the two people could be pulling in the same direction. In this simple one-dimensional example, without knowing the direction of the forces it is impossible to decide whether the net force is the result of adding the two force magnitudes or subtracting one from the other. Associating forces with vectors avoids such problems. | 0.010875 | 0.651374 | 3,360 | 13,504 | 87 | 87 | Energy and Physics Concepts | false |
20,926 | Force | Historically, forces were first quantitatively investigated in conditions of static equilibrium where several forces canceled each other out. Such experiments demonstrate the crucial properties that forces are additive vector quantities: they have magnitude and direction. When two forces act on a point particle, the resulting force, the resultant (also called the net force), can be determined by following the parallelogram rule of vector addition: the addition of two vectors represented by sides of a parallelogram, gives an equivalent resultant vector that is equal in magnitude and direction to the transversal of the parallelogram. The magnitude of the resultant varies from the difference of the magnitudes of the two forces to their sum, depending on the angle between their lines of action. However, if the forces are acting on an extended body, their respective lines of application must also be specified in order to account for their effects on the motion of the body. | 0.010428 | 0.65616 | 3,360 | 13,504 | 87 | 87 | Energy and Physics Concepts | false |
20,927 | Force | As well as being added, forces can also be resolved into independent components at right angles to each other. A horizontal force pointing northeast can therefore be split into two forces, one pointing north, and one pointing east. Summing these component forces using vector addition yields the original force. Resolving force vectors into components of a set of basis vectors is often a more mathematically clean way to describe forces than using magnitudes and directions. This is because, for orthogonal components, the components of the vector sum are uniquely determined by the scalar addition of the components of the individual vectors. Orthogonal components are independent of each other because forces acting at ninety degrees to each other have no effect on the magnitude or direction of the other. Choosing a set of orthogonal basis vectors is often done by considering what set of basis vectors will make the mathematics most convenient. Choosing a basis vector that is in the same direction as one of the forces is desirable, since that force would then have only one non-zero component. Orthogonal force vectors can be three-dimensional with the third component being at right-angles to the other two. | 0.012571 | 0.64694 | 3,360 | 13,504 | 87 | 87 | Energy and Physics Concepts | false |
20,928 | Force | Pushing against an object on a frictional surface can result in a situation where the object does not move because the applied force is opposed by static friction, generated between the object and the table surface. For a situation with no movement, the static friction force exactly balances the applied force resulting in no acceleration. The static friction increases or decreases in response to the applied force up to an upper limit determined by the characteristics of the contact between the surface and the object. | 0.002827 | 0.660667 | 3,424 | 13,632 | 87 | 87 | Energy and Physics Concepts | false |
20,929 | Force | A static equilibrium between two forces is the most usual way of measuring forces, using simple devices such as weighing scales and spring balances. For example, an object suspended on a vertical spring scale experiences the force of gravity acting on the object balanced by a force applied by the "spring reaction force", which equals the object's weight. Using such tools, some quantitative force laws were discovered: that the force of gravity is proportional to volume for objects of constant density (widely exploited for millennia to define standard weights); Archimedes' principle for buoyancy; Archimedes' analysis of the lever; Boyle's law for gas pressure; and Hooke's law for springs. These were all formulated and experimentally verified before Isaac Newton expounded his Three Laws of Motion. | 0.016033 | 0.653973 | 3,360 | 13,505 | 87 | 87 | Energy and Physics Concepts | false |
20,930 | Force | Dynamic equilibrium was first described by Galileo who noticed that certain assumptions of Aristotelian physics were contradicted by observations and logic. Galileo realized that simple velocity addition demands that the concept of an "absolute rest frame" did not exist. Galileo concluded that motion in a constant velocity was completely equivalent to rest. This was contrary to Aristotle's notion of a "natural state" of rest that objects with mass naturally approached. Simple experiments showed that Galileo's understanding of the equivalence of constant velocity and rest were correct. For example, if a mariner dropped a cannonball from the crow's nest of a ship moving at a constant velocity, Aristotelian physics would have the cannonball fall straight down while the ship moved beneath it. Thus, in an Aristotelian universe, the falling cannonball would land behind the foot of the mast of a moving ship. However, when this experiment is actually conducted, the cannonball always falls at the foot of the mast, as if the cannonball knows to travel with the ship despite being separated from it. Since there is no forward horizontal force being applied on the cannonball as it falls, the only conclusion left is that the cannonball continues to move with the same velocity as the boat as it falls. Thus, no force is required to keep the cannonball moving at the constant forward velocity. | 0.032671 | 0.650509 | 3,361 | 13,506 | 87 | 87 | Energy and Physics Concepts | false |
20,931 | Force | A simple case of dynamic equilibrium occurs in constant velocity motion across a surface with kinetic friction. In such a situation, a force is applied in the direction of motion while the kinetic friction force exactly opposes the applied force. This results in zero net force, but since the object started with a non-zero velocity, it continues to move with a non-zero velocity. Aristotle misinterpreted this motion as being caused by the applied force. However, when kinetic friction is taken into consideration it is clear that there is no net force causing constant velocity motion. | 0.022461 | 0.661158 | 3,424 | 13,633 | 87 | 87 | Energy and Physics Concepts | false |
20,932 | Force | The notion "force" keeps its meaning in quantum mechanics, though one is now dealing with operators instead of classical variables and though the physics is now described by the Schrödinger equation instead of Newtonian equations. This has the consequence that the results of a measurement are now sometimes "quantized", i.e. they appear in discrete portions. This is, of course, difficult to imagine in the context of "forces". However, the potentials V(x,y,z) or fields, from which the forces generally can be derived, are treated similar to classical position variables, i.e., . | 0.010776 | 0.660653 | 3,424 | 13,632 | 87 | 87 | Energy and Physics Concepts | false |
20,933 | Force | However, already in quantum mechanics there is one "caveat", namely the particles acting onto each other do not only possess the spatial variable, but also a discrete intrinsic angular momentum-like variable called the "spin", and there is the Pauli principle relating the space and the spin variables. Depending on the value of the spin, identical particles split into two different classes, fermions and bosons. If two identical fermions (e.g. electrons) have a symmetric spin function (e.g. parallel spins) the spatial variables must be antisymmetric (i.e. they exclude each other from their places much as if there was a repulsive force), and vice versa, i.e. for antiparallel spins the position variables must be symmetric (i.e. the apparent force must be attractive). Thus in the case of two fermions there is a strictly negative correlation between spatial and spin variables, whereas for two bosons (e.g. quanta of electromagnetic waves, photons) the correlation is strictly positive. | -0.005736 | 0.655892 | 3,359 | 13,503 | 87 | 87 | Energy and Physics Concepts | false |
20,934 | Force | In modern particle physics, forces and the acceleration of particles are explained as a mathematical by-product of exchange of momentum-carrying gauge bosons. With the development of quantum field theory and general relativity, it was realized that force is a redundant concept arising from conservation of momentum (4-momentum in relativity and momentum of virtual particles in quantum electrodynamics). The conservation of momentum can be directly derived from the homogeneity or symmetry of space and so is usually considered more fundamental than the concept of a force. Thus the currently known fundamental forces are considered more accurately to be "fundamental interactions".:199–128 When particle A emits (creates) or absorbs (annihilates) virtual particle B, a momentum conservation results in recoil of particle A making impression of repulsion or attraction between particles A A' exchanging by B. This description applies to all forces arising from fundamental interactions. While sophisticated mathematical descriptions are needed to predict, in full detail, the accurate result of such interactions, there is a conceptually simple way to describe such interactions through the use of Feynman diagrams. In a Feynman diagram, each matter particle is represented as a straight line (see world line) traveling through time, which normally increases up or to the right in the diagram. Matter and anti-matter particles are identical except for their direction of propagation through the Feynman diagram. World lines of particles intersect at interaction vertices, and the Feynman diagram represents any force arising from an interaction as occurring at the vertex with an associated instantaneous change in the direction of the particle world lines. Gauge bosons are emitted away from the vertex as wavy lines and, in the case of virtual particle exchange, are absorbed at an adjacent vertex. | 0.001629 | 0.658612 | 3,424 | 13,632 | 87 | 87 | Energy and Physics Concepts | false |
20,935 | Force | All of the forces in the universe are based on four fundamental interactions. The strong and weak forces are nuclear forces that act only at very short distances, and are responsible for the interactions between subatomic particles, including nucleons and compound nuclei. The electromagnetic force acts between electric charges, and the gravitational force acts between masses. All other forces in nature derive from these four fundamental interactions. For example, friction is a manifestation of the electromagnetic force acting between the atoms of two surfaces, and the Pauli exclusion principle, which does not permit atoms to pass through each other. Similarly, the forces in springs, modeled by Hooke's law, are the result of electromagnetic forces and the Exclusion Principle acting together to return an object to its equilibrium position. Centrifugal forces are acceleration forces that arise simply from the acceleration of rotating frames of reference.:12-11:359 | 0.008117 | 0.657938 | 3,424 | 13,632 | 87 | 87 | Energy and Physics Concepts | false |
20,936 | Force | The development of fundamental theories for forces proceeded along the lines of unification of disparate ideas. For example, Isaac Newton unified the force responsible for objects falling at the surface of the Earth with the force responsible for the orbits of celestial mechanics in his universal theory of gravitation. Michael Faraday and James Clerk Maxwell demonstrated that electric and magnetic forces were unified through one consistent theory of electromagnetism. In the 20th century, the development of quantum mechanics led to a modern understanding that the first three fundamental forces (all except gravity) are manifestations of matter (fermions) interacting by exchanging virtual particles called gauge bosons. This standard model of particle physics posits a similarity between the forces and led scientists to predict the unification of the weak and electromagnetic forces in electroweak theory subsequently confirmed by observation. The complete formulation of the standard model predicts an as yet unobserved Higgs mechanism, but observations such as neutrino oscillations indicate that the standard model is incomplete. A Grand Unified Theory allowing for the combination of the electroweak interaction with the strong force is held out as a possibility with candidate theories such as supersymmetry proposed to accommodate some of the outstanding unsolved problems in physics. Physicists are still attempting to develop self-consistent unification models that would combine all four fundamental interactions into a theory of everything. Einstein tried and failed at this endeavor, but currently the most popular approach to answering this question is string theory.:212–219 | 0.000122 | 0.650069 | 3,360 | 13,504 | 87 | 87 | Energy and Physics Concepts | false |
20,937 | Force | What we now call gravity was not identified as a universal force until the work of Isaac Newton. Before Newton, the tendency for objects to fall towards the Earth was not understood to be related to the motions of celestial objects. Galileo was instrumental in describing the characteristics of falling objects by determining that the acceleration of every object in free-fall was constant and independent of the mass of the object. Today, this acceleration due to gravity towards the surface of the Earth is usually designated as and has a magnitude of about 9.81 meters per second squared (this measurement is taken from sea level and may vary depending on location), and points toward the center of the Earth. This observation means that the force of gravity on an object at the Earth's surface is directly proportional to the object's mass. Thus an object that has a mass of will experience a force: | 0.021344 | 0.653803 | 3,360 | 13,505 | 87 | 87 | Energy and Physics Concepts | false |
20,938 | Force | Newton came to realize that the effects of gravity might be observed in different ways at larger distances. In particular, Newton determined that the acceleration of the Moon around the Earth could be ascribed to the same force of gravity if the acceleration due to gravity decreased as an inverse square law. Further, Newton realized that the acceleration due to gravity is proportional to the mass of the attracting body. Combining these ideas gives a formula that relates the mass () and the radius () of the Earth to the gravitational acceleration: | 0.026907 | 0.650962 | 3,360 | 13,505 | 87 | 87 | Energy and Physics Concepts | false |
20,939 | Force | In this equation, a dimensional constant is used to describe the relative strength of gravity. This constant has come to be known as Newton's Universal Gravitation Constant, though its value was unknown in Newton's lifetime. Not until 1798 was Henry Cavendish able to make the first measurement of using a torsion balance; this was widely reported in the press as a measurement of the mass of the Earth since knowing could allow one to solve for the Earth's mass given the above equation. Newton, however, realized that since all celestial bodies followed the same laws of motion, his law of gravity had to be universal. Succinctly stated, Newton's Law of Gravitation states that the force on a spherical object of mass due to the gravitational pull of mass is | 0.027457 | 0.649724 | 3,360 | 13,505 | 87 | 87 | Energy and Physics Concepts | false |
20,940 | Force | It was only the orbit of the planet Mercury that Newton's Law of Gravitation seemed not to fully explain. Some astrophysicists predicted the existence of another planet (Vulcan) that would explain the discrepancies; however, despite some early indications, no such planet could be found. When Albert Einstein formulated his theory of general relativity (GR) he turned his attention to the problem of Mercury's orbit and found that his theory added a correction, which could account for the discrepancy. This was the first time that Newton's Theory of Gravity had been shown to be less correct than an alternative. | 0.049616 | 0.636485 | 3,361 | 13,379 | 87 | 87 | Energy and Physics Concepts | false |
20,941 | Force | Since then, and so far, general relativity has been acknowledged as the theory that best explains gravity. In GR, gravitation is not viewed as a force, but rather, objects moving freely in gravitational fields travel under their own inertia in straight lines through curved space-time – defined as the shortest space-time path between two space-time events. From the perspective of the object, all motion occurs as if there were no gravitation whatsoever. It is only when observing the motion in a global sense that the curvature of space-time can be observed and the force is inferred from the object's curved path. Thus, the straight line path in space-time is seen as a curved line in space, and it is called the ballistic trajectory of the object. For example, a basketball thrown from the ground moves in a parabola, as it is in a uniform gravitational field. Its space-time trajectory (when the extra ct dimension is added) is almost a straight line, slightly curved (with the radius of curvature of the order of few light-years). The time derivative of the changing momentum of the object is what we label as "gravitational force". | 0.04997 | 0.638576 | 3,361 | 13,379 | 87 | 87 | Energy and Physics Concepts | false |
20,942 | Force | Through combining the definition of electric current as the time rate of change of electric charge, a rule of vector multiplication called Lorentz's Law describes the force on a charge moving in a magnetic field. The connection between electricity and magnetism allows for the description of a unified electromagnetic force that acts on a charge. This force can be written as a sum of the electrostatic force (due to the electric field) and the magnetic force (due to the magnetic field). Fully stated, this is the law: | -0.009555 | 0.6645 | 3,423 | 13,631 | 87 | 87 | Energy and Physics Concepts | false |
20,943 | Force | The origin of electric and magnetic fields would not be fully explained until 1864 when James Clerk Maxwell unified a number of earlier theories into a set of 20 scalar equations, which were later reformulated into 4 vector equations by Oliver Heaviside and Josiah Willard Gibbs. These "Maxwell Equations" fully described the sources of the fields as being stationary and moving charges, and the interactions of the fields themselves. This led Maxwell to discover that electric and magnetic fields could be "self-generating" through a wave that traveled at a speed that he calculated to be the speed of light. This insight united the nascent fields of electromagnetic theory with optics and led directly to a complete description of the electromagnetic spectrum. | -0.027378 | 0.641325 | 3,359 | 13,502 | 87 | -1 | Energy and Physics Concepts | false |
20,944 | Force | However, attempting to reconcile electromagnetic theory with two observations, the photoelectric effect, and the nonexistence of the ultraviolet catastrophe, proved troublesome. Through the work of leading theoretical physicists, a new theory of electromagnetism was developed using quantum mechanics. This final modification to electromagnetic theory ultimately led to quantum electrodynamics (or QED), which fully describes all electromagnetic phenomena as being mediated by wave–particles known as photons. In QED, photons are the fundamental exchange particle, which described all interactions relating to electromagnetism including the electromagnetic force.[Note 4] | -0.03081 | 0.64497 | 3,359 | 13,502 | 87 | -1 | Energy and Physics Concepts | false |
20,945 | Force | It is a common misconception to ascribe the stiffness and rigidity of solid matter to the repulsion of like charges under the influence of the electromagnetic force. However, these characteristics actually result from the Pauli exclusion principle.[citation needed] Since electrons are fermions, they cannot occupy the same quantum mechanical state as other electrons. When the electrons in a material are densely packed together, there are not enough lower energy quantum mechanical states for them all, so some of them must be in higher energy states. This means that it takes energy to pack them together. While this effect is manifested macroscopically as a structural force, it is technically only the result of the existence of a finite set of electron states. | 0.002752 | 0.658194 | 3,424 | 13,632 | 87 | 87 | Energy and Physics Concepts | false |
20,946 | Force | The strong force only acts directly upon elementary particles. However, a residual of the force is observed between hadrons (the best known example being the force that acts between nucleons in atomic nuclei) as the nuclear force. Here the strong force acts indirectly, transmitted as gluons, which form part of the virtual pi and rho mesons, which classically transmit the nuclear force (see this topic for more). The failure of many searches for free quarks has shown that the elementary particles affected are not directly observable. This phenomenon is called color confinement. | 0.0043 | 0.659146 | 3,424 | 13,632 | 87 | 87 | Energy and Physics Concepts | false |
20,947 | Force | The weak force is due to the exchange of the heavy W and Z bosons. Its most familiar effect is beta decay (of neutrons in atomic nuclei) and the associated radioactivity. The word "weak" derives from the fact that the field strength is some 1013 times less than that of the strong force. Still, it is stronger than gravity over short distances. A consistent electroweak theory has also been developed, which shows that electromagnetic forces and the weak force are indistinguishable at a temperatures in excess of approximately 1015 kelvins. Such temperatures have been probed in modern particle accelerators and show the conditions of the universe in the early moments of the Big Bang. | 0.009042 | 0.664803 | 3,424 | 13,632 | 87 | 87 | Energy and Physics Concepts | false |
20,948 | Force | The normal force is due to repulsive forces of interaction between atoms at close contact. When their electron clouds overlap, Pauli repulsion (due to fermionic nature of electrons) follows resulting in the force that acts in a direction normal to the surface interface between two objects.:93 The normal force, for example, is responsible for the structural integrity of tables and floors as well as being the force that responds whenever an external force pushes on a solid object. An example of the normal force in action is the impact force on an object crashing into an immobile surface. | 0.015678 | 0.652048 | 3,360 | 13,505 | 87 | 87 | Energy and Physics Concepts | false |
20,949 | Force | Tension forces can be modeled using ideal strings that are massless, frictionless, unbreakable, and unstretchable. They can be combined with ideal pulleys, which allow ideal strings to switch physical direction. Ideal strings transmit tension forces instantaneously in action-reaction pairs so that if two objects are connected by an ideal string, any force directed along the string by the first object is accompanied by a force directed along the string in the opposite direction by the second object. By connecting the same string multiple times to the same object through the use of a set-up that uses movable pulleys, the tension force on a load can be multiplied. For every string that acts on a load, another factor of the tension force in the string acts on the load. However, even though such machines allow for an increase in force, there is a corresponding increase in the length of string that must be displaced in order to move the load. These tandem effects result ultimately in the conservation of mechanical energy since the work done on the load is the same no matter how complicated the machine. | -0.004094 | 0.661605 | 3,423 | 13,631 | 87 | 87 | Energy and Physics Concepts | false |
20,950 | Force | Newton's laws and Newtonian mechanics in general were first developed to describe how forces affect idealized point particles rather than three-dimensional objects. However, in real life, matter has extended structure and forces that act on one part of an object might affect other parts of an object. For situations where lattice holding together the atoms in an object is able to flow, contract, expand, or otherwise change shape, the theories of continuum mechanics describe the way forces affect the material. For example, in extended fluids, differences in pressure result in forces being directed along the pressure gradients as follows: | 0.010225 | 0.659413 | 3,424 | 13,632 | 87 | 87 | Energy and Physics Concepts | false |
20,951 | Force | where is the relevant cross-sectional area for the volume for which the stress-tensor is being calculated. This formalism includes pressure terms associated with forces that act normal to the cross-sectional area (the matrix diagonals of the tensor) as well as shear terms associated with forces that act parallel to the cross-sectional area (the off-diagonal elements). The stress tensor accounts for forces that cause all strains (deformations) including also tensile stresses and compressions.:133–134:38-1–38-11 | 0.008153 | 0.661415 | 3,424 | 13,632 | 87 | 87 | Energy and Physics Concepts | false |
20,952 | Force | Torque is the rotation equivalent of force in the same way that angle is the rotational equivalent for position, angular velocity for velocity, and angular momentum for momentum. As a consequence of Newton's First Law of Motion, there exists rotational inertia that ensures that all bodies maintain their angular momentum unless acted upon by an unbalanced torque. Likewise, Newton's Second Law of Motion can be used to derive an analogous equation for the instantaneous angular acceleration of the rigid body: | 0.018221 | 0.650027 | 3,360 | 13,505 | 87 | 87 | Energy and Physics Concepts | false |
20,953 | Force | where is the mass of the object, is the velocity of the object and is the distance to the center of the circular path and is the unit vector pointing in the radial direction outwards from the center. This means that the unbalanced centripetal force felt by any object is always directed toward the center of the curving path. Such forces act perpendicular to the velocity vector associated with the motion of an object, and therefore do not change the speed of the object (magnitude of the velocity), but only the direction of the velocity vector. The unbalanced force that accelerates an object can be resolved into a component that is perpendicular to the path, and one that is tangential to the path. This yields both the tangential force, which accelerates the object by either slowing it down or speeding it up, and the radial (centripetal) force, which changes its direction. | 0.018256 | 0.649302 | 3,360 | 13,505 | 87 | 87 | Energy and Physics Concepts | false |
20,954 | Force | A conservative force that acts on a closed system has an associated mechanical work that allows energy to convert only between kinetic or potential forms. This means that for a closed system, the net mechanical energy is conserved whenever a conservative force acts on the system. The force, therefore, is related directly to the difference in potential energy between two different locations in space, and can be considered to be an artifact of the potential field in the same way that the direction and amount of a flow of water can be considered to be an artifact of the contour map of the elevation of an area. | 0.014267 | 0.660208 | 3,424 | 13,632 | 87 | 87 | Energy and Physics Concepts | false |
20,955 | Force | For certain physical scenarios, it is impossible to model forces as being due to gradient of potentials. This is often due to macrophysical considerations that yield forces as arising from a macroscopic statistical average of microstates. For example, friction is caused by the gradients of numerous electrostatic potentials between the atoms, but manifests as a force model that is independent of any macroscale position vector. Nonconservative forces other than friction include other contact forces, tension, compression, and drag. However, for any sufficiently detailed description, all these forces are the results of conservative ones since each of these macroscopic forces are the net results of the gradients of microscopic potentials. | 0.011607 | 0.656263 | 3,424 | 13,632 | 87 | 87 | Energy and Physics Concepts | false |
20,956 | Force | The connection between macroscopic nonconservative forces and microscopic conservative forces is described by detailed treatment with statistical mechanics. In macroscopic closed systems, nonconservative forces act to change the internal energies of the system, and are often associated with the transfer of heat. According to the Second law of thermodynamics, nonconservative forces necessarily result in energy transformations within closed systems from ordered to more random conditions as entropy increases. | 0.006796 | 0.668854 | 3,424 | 13,632 | 87 | 87 | Energy and Physics Concepts | false |
20,957 | Force | The pound-force has a metric counterpart, less commonly used than the newton: the kilogram-force (kgf) (sometimes kilopond), is the force exerted by standard gravity on one kilogram of mass. The kilogram-force leads to an alternate, but rarely used unit of mass: the metric slug (sometimes mug or hyl) is that mass that accelerates at 1 m·s−2 when subjected to a force of 1 kgf. The kilogram-force is not a part of the modern SI system, and is generally deprecated; however it still sees use for some purposes as expressing aircraft weight, jet thrust, bicycle spoke tension, torque wrench settings and engine output torque. Other arcane units of force include the sthène, which is equivalent to 1000 N, and the kip, which is equivalent to 1000 lbf. | 0.021903 | 0.650093 | 3,360 | 13,505 | 87 | 87 | Energy and Physics Concepts | false |
Subsets and Splits