Answer the following question given this paragraph: So does the magnetic force cause circular motion? Magnetic force is always perpendicular to velocity, so that it does no work on the charged particle. The particle's kinetic energy and speed thus remain constant. The direction of motion is affected, but not the speed. This is typical of uniform circular motion. The simplest case occurs when a charged particle moves perpendicular to a uniform B -field, such as shown in Figure 22.20. (If this takes place in a vacuum, the magnetic field is the dominant factor determining the motion. ) Here, the magnetic force supplies the centripetal force F c = mv 2 / r . Noting that sin = 1 , we see that. Q: Magnetic force is always perpendicular to what? A:

OPTIONS:
- speed
- sunlight
- length
- velocity

Answer: velocity

Problem: OPTIONS:
- turbulence
- permeability
- elasticity
- viscosity
Q: Answer the following question given this paragraph: Viscosity () is the resistance of a liquid to flow. Some liquids, such as gasoline, ethanol, and water, flow very readily and hence have a low viscosity. Others, such as motor oil, molasses, and maple syrup, flow very slowly and have a high viscosity. The two most common methods for evaluating the viscosity of a liquid are (1) to measure the time it takes for a quantity of liquid to flow through a narrow vertical tube and (2) to measure the time it takes steel balls to fall through a given volume of the liquid. The higher the viscosity, the slower the liquid flows through the tube and the steel balls fall. Viscosity is expressed in units of the poise (mPas); the higher the number, the higher the viscosity. The viscosities of some representative liquids are listed in Table 11.4 "Surface Tension, Viscosity, Vapor Pressure (at 25C Unless Otherwise Indicated), and Normal Boiling Points of Common Liquids" and show a correlation between viscosity and intermolecular forces. Because a liquid can flow only if the molecules can move past one another with minimal resistance, strong intermolecular attractive forces make it more difficult for molecules to move with respect to one another. The addition of a second hydroxyl group to ethanol, for example, which produces ethylene glycol (HOCH2CH2OH), increases the viscosity 15-fold. This effect is due to the increased number of hydrogen bonds that can form between hydroxyl groups in adjacent molecules, resulting in dramatically stronger intermolecular attractive forces. Q: What is the resistance of a liquid to flow called? A:
Answer: viscosity

Problem:OPTIONS:
- dries
- heats
- warms
- cools

Answer the following question given this paragraph: The rising air cools as it reaches the top of the troposphere. The air gets denser, so it sinks to the surface. The sinking, heavy air creates an area of high air pressure near the ground. Q: What does rising air do when it reaches the top of the troposphere? A:
****
A: cools

Answer the following question given this paragraph: This increase in global temperature will cause the sea level to rise. It is also expected to produce an increase in extreme weather events and change the amount of precipitation. Global warming may also cause food shortages and species extinction. Q: What will happen to sea levels due to increased global temperatures? A:
OPTIONS:
- Drop
- reverse
- surge
- rise
rise

Answer the following question given this paragraph: Secondary succession A classic example of secondary succession occurs in oak and hickory forests cleared by wildfire (Figure 19.27). Wildfires will burn most vegetation, and unless the animals can flee the area, they are killed. Their nutrients, however, are returned to the ground in the form of ash. Thus, although the community has been dramatically altered, there is a soil ecosystem present that provides a foundation for rapid recolonization. Before the fire, the vegetation was dominated by tall trees with access to the major plant energy resource: sunlight. Their height gave them access to sunlight while also shading the ground and other low-lying species. After the fire, though, these trees are no longer dominant. Thus, the first plants to grow back are usually annual plants followed within a few years by quickly growing and spreading grasses and other pioneer species. Due, at least in part, to changes in the environment brought on by the growth of grasses and forbs, over many years, shrubs emerge along with small pine, oak, and hickory trees. These organisms are called intermediate species. Eventually, over 150 years, the forest will reach its equilibrium point and resemble the community before the fire. This equilibrium state is referred to as the climax community, which will remain until the next disturbance. The climax community is typically characteristic of a given climate and geology. Although the community in equilibrium looks the same once it is attained, the equilibrium is a dynamic one with constant changes in abundance and sometimes species identities. The return of a natural ecosystem after agricultural activities is also a well-documented secondary succession process. Q: A wildfire clears a forest of vegetation and animal life, returning their nutrients to the ground leaving a foundation for rapid recolonization. what is this a classic example of? A:
OPTIONS:
- primary succession
- typical succession
- cause succession
- secondary succession

Answer: secondary succession

input with options: Answer the following question given this paragraph: Thermal pollution raises the temperature of water. It is commonly caused by power plants and factories. The change in temperature can kill fish and other water organisms. Q: What type of pollution is generated by power plants and factories that can directly raise the temperature of water? A:
OPTIONS:
- atmospheric pollution
- Space Pollution
- variable pollution
- thermal pollution
output:
thermal pollution