1. Momentum, work, power and energy review problems

2. Problem 1
Amy is carrying a 100 kg box across the floor a distance of 10.0 m. How much work is done on the box? None

3. Problem 2
If Amy were lifting the same box up a distance of 1.4 m, how much work is done on the box? 1372 J

4. Problem 3
If Amy takes 1.4 seconds to lift the box in #2, how much power does she use? 980 W

5. Problem 4
A 398 kg crate is pushed across the floor for a distance of 62.5 m. If the applied force on the crate is 931 N and the surface is frictionless, what is the work done on the crate? J

6. Problem 5
A 12.9kg bicycle accelerates from rest to 2.3 m/s in 4.1 s. What is the change in momentum of the bike? What is the average force exerted on the bicycle to impart this momentum?
29.67 kgm/s
7.2 N

7. Problem 6
2 Trains collide inelastically! A Northbound Train has a mass of 3121 kg and a speed of 82 m/s and Southbound Train has a mass of 2014 kg with speed of 23 m/s. Find their final velocity. 41 m/s North

8. Problem 7
An 18 g bullet is shot into a 4.03 kg wooden block standing on a frictionless surface. The block, with the bullet in it, acquires a velocity of 1.5 m/s. Calculate the velocity of the bullet before striking the block. 337 m/s

9. Problem 8
A 0.25 kg red marble traveling right at 2.0 m/s collides head-on with a 0.50 kg green marble moving 1.5 m/s left. What is the final velocity of green marble if the red marble moves left at 1.2 m/s? 0.10 m/s right

10. Problem 9
While chasing the roadrunner, the 30 kg coyote falls off a 900 m cliff.
How much potential energy does the coyote have at the top of the cliff?
How much kinetic energy does the coyote have right before he hits the ground? J

11. Problem 10
A 4.0 kg bucket is thrown out a 3.0 m high window at a speed of 2.1 m/s. Assuming no air resistance, what is the speed just before the bucket hits the ground? -8.0 m/s

12. Problem 11
2 hockey pucks collide elastically. Puck 1 has a mass of kg and a speed to the right of 2.1 m/s. Puck 2 has a mass of kg and a speed to the left of 4.2 m/s. After the collision Puck 1 has a speed to the left of 1.9 m/s. What is the speed of Puck 2? 0.45 m/s