Acid rain contributes to soil erosion. Acid rain can be caused by A. chemicals released into the air by motor vehicles B. drought C. sudden cloud formation D. over fertilization of farmlands Save

How do simple machines make work easier? A. They add energy to the work. B. They increase the force needed to work. C. They reduce the speed of work. D. They increase the distance over which a force is applied.

A cord runs around two pulleys. A canister of mass 20 kg hangs from one pulley, and you exert a force on the free end of the cord.

What is spectroscopy? a) the use of ccds to capture light more ef? ciently than with photographic? lm b) an analysis of the way in which atoms absorb and emit light c) a study of the geometry of rainbows d) a method to freeze atmospheric turbulence

How does an atom of potassium-41 become a potassium ion with a + 1 charge? 19 K 39.10 A. The atom gains 1 proton, to make a total of 20. B. The atom loses 1 electron, to make a total of 18. C. The atom gains 1 proton, to make a total of 42. D.

The atomic mass unit is

Why does the moon appear to change shape? A: It rotates and makes it own light B: It moves closer and farther away from the earth in a yearly pattern. C: It reflects sunlight as it revolves around the earth.

An object's weight is equal to its buoyant force in water. What would you expect to happen when the object is placed in water? Explain your reasoning.

What is the name of the german scientist that proposed the theory of continental drift

Trucks 1 and 2 are traveling at the same constant velocity but truck 1's energy due to motion is two times less than that of truck 2. This is because Truck 1's mass is:

Why do the densities of most substances decrease with an increase in temperature?