1. A ball is thrown directly up at 30 m/s. What is its "displacement from the ground", velocity and acceleration at:
   1. 2 seconds after throwing:
   2. 3 seconds after throwing:
   3. 5 seconds after throwing:
2. For the ball in number 1: how does its speed at a height of 25 meters on the way up compare to its speed at a height of 25 meters on the way down?
3. How is motion of the baseball different if we fill it with lead just before throwing it up at 30 m/s?
5. What is the displacement where a runner goes at 5 m/s for 250 seconds?
6. What is the magnitude of the total displacement where a hiker travels 25 km north in the morning then 15 km east in the afternoon?
7. What is the rate of acceleration if a car begins at rest and makes 25 m/s after 10 seconds?
8. What rate of acceleration is required to change speed from 30 m/s to 5 m/s in 10 seconds?
9. How much work is required to lift a 4 kg mass to a height of 9 meters?
10. How much power is required to lift a 4 kg mass to a height of 9 meters in 5 seconds?
11. How much work is required to lift a 4 N weight to a height of 9 meters?
12. A circus diver jumps from 125 meters.
    1. How much potential energy does he have at the top?
    2. How much kinetic energy does he have at a height of 45 meters?
    3. How fast is he falling just before he hits the ground?
13. How much work is required to stop a 25 kg wagon moving at 12 m/s?
14. Over what distance must a 20 N force act in order to stop a 25 kg wagon initially moving at 12 m/s?
15. How much momentum does a 25 kg wagon moving at 12 m/s have?
16. A 1.0 kg dynamics cart moves east at 0.6 m/s. A second cart of mass 0.5 kg moves west at 0.8 m/s. They collide and couple. If momentum is conserved, how fast do the two carts travel together after the collision?
17. A 25 kg wagon initially moving at 12 m/s is brought to a stop in 3 seconds. What net force must act on it?
18. If 25 N•s of impulse is imparted on a baseball in .015 seconds, what is the average force of impact?
19. Why does an airbag save you from death in a front-end collision?
20. A 25 kg wagon slows down from 12 m/s to 5 m/s. By how much does its momentum change?
21. A 25 kg wagon comes to rest from 12 m/s with an average force of 6 N. Over how much time did the braking occur?
22. A 210 kg refrigerator is dragged at constant speed by a force of 225 N. What is the force of friction exerted against the refrigerator by the floor?
23. A 210 kg refrigerator is dragged at constant speed by a force of 225 N. What is the coefficient of friction between the refrigerator and the floor?