1. A girl rides a bike. The pedals move a shorter distance than the wheels. In return, she uses _____ if she turns the wheels directly.

a. half of the force than

b. smaller force than

c. bigger force than

d. the same force as

2. In the class video about the pendulum experiment, the teacher was not concerned about being hit on the face since the ball:

a. would stop by a safety mechanism.

b. total energy could not increase.

c. would stop in the middle.

d. total energy would increase.

3. A student has a mass of 70 kg. She runs with a speed exactly 10 m/s. Her kinetic energy is _____ kJ.

4. In laser eye surgery, the average laser pulse power is 60 kW, and contains 1 mJ of light energy. Each laser pulse lasts _____ nanosecond.

5.Consider momentum. What has the most impulse in a car crash, to have our car:

a. stop right there.

b. slow down.

c. keep moving forward.

d. bounce backward.

6. When a bullet is shot, the gun gains a momentum _____ the bullet.

a. less magnitude than

b. the same direction as

c. the same magnitude as

d. greater magnitude than

7. In the class demo of throwing an egg, the egg did not break since the _____ was tiny.

a. mass

b. momentum

c. speed

d. force

8. A collision does not cause damage for a bumper car since it has:

a. collision avoidance.

b. increased contact time.

c. seat belts.

d. little momentum.

9. In a car crash, adding up all the cars, the sum total _____ is always conserved.

a. velocity

b. momentum

c. distance traveled

d. energy

10. A spaceship with fuel is initially at rest at point CG. Fuel is ejected at the back to propel the payload to the forward direction. After a long time, the total fuel ejected out has a mass of 10⁶ pounds, and center of gravity moving backward at 20 m/s. The forward speed of the payload relative to CG is 150 m/s. The payload mass is _____ pounds.

11. Two cars in opposite directions were going at 50 mph before a collision. They had a head on inelastic collision, i.e. the two cars stuck together afterward. The common speed of the combined piece right after the collision is 20 mph. The mass of Car 1 was 2,000 lb. Car 2 was heavier. The mass of Car 2 was ____ lb.