Vector, in physics, a quantity that has both magnitude and direction. It is typically represented by an arrow whose direction is the same as that of the quantity and whose length is proportional to the quantityâs magnitude. Although a vector has magnitude and direction, it does not have position. That is, as long as its length is not changed, a vector is not altered if it is displaced parallel to itself. In contrast to vectors, ordinary quantities that have a magnitude but not a direction are called scalars. For example, displacement, velocity, and acceleration are vector quantities, while speed (the magnitude of velocity), time, and mass are scalars. To qualify as a vector, a quantity having magnitude and direction must also obey certain rules of combination.
Correct Answer: An explosive stratovolcano. Feedback: Good work Question 4 4 out of 4 points What are usually the most abundant gases emitted during basaltic volcanism (as measured during Hawaiian eruptions)? Selected Answer: Water and carbon dioxide Correct Answer: Water and carbon dioxide Feedback: Good work.
By far, the most abundant gas in the Earth's atmosphere is nitrogen, which accounts for about 78% of the mass of dry air. Oxygen is the next most abundant gas, present at levels of 20 to 21%. Although humid air seems like it contains a lot of water, the maximum amount of water vapor that air can hold is only about 4%. Abundance of Gases in the Atmosphere. This table lists the eleven most abundant gases in the lower portion of Earth's atmosphere (up to 25 km). While the percentage of nitrogen and oxygen are fairly stable, the amount of greenhouse gases changes and depends on location. Water vapor is extremely variable.