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1) A box is supported by a 4.4 N vertical force and carried 1.7 m horizontally across a room at constant speed. Then, the same box is pushed 1.7 m horizontally across a smooth table (smooth enough to ignore friction) by a 4.4 N horizontal force. In which case was more work done on the box by the 4.4 N force?

a. More work was done when the box was carried across the room.

b. The work was the same in each case, since the force and distance were of equal magnitudes in both situations.

c. More work was done when the box was pushed across the table.

2) A loaded gun is dropped on a frozen lake. The gun fires, with the bullet going horizontally in one direction and the gun sliding on the ice in the other direction. The bullet's mass is 0.04 kg, and its speed is 325 m/s. If the gun's mass is 2.2 kg, what is its speed (in m/s)?

3) A 35 kg child uses a pogo stick to bounce up and down. The spring constant, k, of the toy equals 9,200 N/m.

a. By how much would the spring be compressed by the child if she simply balanced herself vertically on the pedals of the stick? (Give your answer in cm.)

b. How much energy (in J) is stored in the spring under this circumstance?

4) A 7,800-kg truck runs into the rear of a 1,000-kg car that was stationary. The truck and car are locked together after the collision and move with speed 8 m/s. Compute how much kinetic energy was "lost" in this inelastic collision. ___J

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

a. friction

b. collisions

c. gravity

d. diffusion

6) A sprinter with a mass of 79 kg reaches a speed of 9 m/s during a race. Find the sprinter's linear momentum (in kg m/s). (Enter the magnitude.) ____kg * m/s

7) Which has the larger linear momentum: a 1,500-kg houseboat going 8 m/s or a 700-kg speedboat going 15 m/s?

a. houseboat

b. speedboat

8) Using the alternate form of Newton's second law, compute the force (in N) needed to accelerate a 1,190 kg car from 0 to 18 m/s in 20 s. The change in momentum is the car's momentum when traveling 18 m/s minus its momentum when going 0 m/s. (Enter the magnitude.)

9) A runner with a mass of 79 kg accelerates from 0 to 6 m/s in 4 s. Find the net force on the runner using the alternate form of Newton's second law. ___N

10 ) A pitcher throws a 0.60 kg ball of clay at a 2.0 kg block of wood. The clay sticks to the wood on impact, and their joint velocity afterward is 1.9 m/s. What was the original speed of the clay (in m/s)?

11) A running back with a mass of 90 kg and a speed of 7 m/s collides with, and is held by, a 135-kg defensive tackle going in the opposite direction. How fast must the tackle be going before the collision for their speed afterward to be zero? _____m/s

12) A motorist runs out of gas on a level road 210 m from a gas station. The driver pushes the 1,180 kg car to the gas station. If a 190 N force is required to keep the car moving, how much work (in J) does the driver do? ____J