1. What is a conservation law? What is the basic approach taken when using a conservation law?

2. Could the linear momentum of a turtle be greater than the linear momentum of a horse? Explain why or why not.

3. For what type of interaction between bodies is the law of conservation of linear momentum most useful?

4. If we know that a force of 5 N acts on an object while it moves 2 meters, can we calculate how much work was done with no other information? Explain.

5. When climbing a flight of stairs, do you do work on the stairs? Do the stairs do work on you?

6. Identify as many different ways as you can for giving energy to a basketball.

7. When you throw a ball, the work you do to accelerate it equals the kinetic energy the ball gains. If you do twice as much work when throwing the ball, does it go twice as fast? Explain.

8. How can the gravitational potential energy of something be negative?

9. If a spring is compressed to half its length, by how much does the amount of energy stored in the spring change?

10. Solar-powered spotlights have batteries that are charged by solar cells during the day and then operate lights at night. Describe the energy conversions in this entire process, starting with the Sun's nuclear energy and ending with the light from the spotlight being absorbed by the surroundings. Name all of the forms of energy that are involved.

11. If you hold a rubber ball at eye level and drop it, it will bounce back, but not to its original height. Identify the energy conversions that take place during the process, and explain why the ball does not reach its original release level.

12. Carts A and B stick together whenever they collide. The mass of A is twice the mass of B. How could you roll the carts toward each other in such a way that they would be stopped after the collision? (Assume there is no friction and that the carts move on level ground.)

13. How are the physical concepts power and speed similar?

14. A person runs up several flights of stairs and is exhausted at the top. Later, the same person walks up the same stairs and does not feel as tired. Why is this? Ignoring air resistance, does it take more work or energy to run up the stairs than to walk up?

15. Why do divers executing midair somersaults pull their legs in against their bodies?

16. Five identical boxes with the same speeds slide along a frictionless horizontal surface. The mass of each box is 10 kg. The same magnitude force, F, is applied to each box, but along different directions. Rank the five situations described here from greatest to smallest according to the work done on the box by the force while the box moves through the distance d indicated each description. For this analysis, take motion/distance directed to the right as positive and force directed up as positive. If any of the situations result in the same work being done, give them the same ranking. (a) F to the right, and d = 5 m to the right (b) F to the right, and d =10 m to the right (c) F up, and d = 10 m to the right (d) F to the left, and d = 5 m to the right (e) F down, and d = 5 m to the right

17. Six blocks with different masses, m, each start from rest at the top of smooth, frictionless inclines having length d and vertical height h and slide down. Rank the order, from greatest to smallest, of the final kinetic energies of the masses when they reach the bottom of the inclines after having traveled their full lengths. If any of the situations yield the same kinetic energies, give them the same ranking.

(a) m = 10 kg; h = 1 m; and d = 10 m

(b) m = 10 kg; h = 1 m; and d = 5 m (c) m = 5 kg; h = 0.5 m; and d = 10 m

(d) m = 1 kg; h = 2 m; and d = 5 m (e) m = 1 kg; h = 0.5 m; and d = 5 m (f) m = 15 kg; h = 0.75 m; and d = 7.5 m