Pick the right answer for each question

1. In order for work to be done, an object must move

• a. The opposite direction of the force being applied
• b. It doesn't have to move
• c. Toward the center of the earth
• d. The same direction as the force being applied

2. What is the formula for work?

• a. W = F*d
• b. w = F*m
• c. W = F/m
• d. W = F/d

3. How much work is required for an 80 kg student to climb a 3 m tall staircase?

• a. 2352 J
• b. 1352 J
• c. 3352 J
• d. 4352 J

4. How much work is required for a student who weighs 800 N to climb a 4 m tall staircase?

• 3200 J
• 200 J
• 804 J
• 2400 J

5. Momentum is a vector, which means it has a ___________ and a ____________.Responses

• magnitude, direction
• front, back
• height, weight
• beginning, end

6. If you are pushing on a 1,000 kg box that is sitting on the floor for 30 seconds and it moves 0 m, how much work are you doing?

• 1000 J
• 30,000 J
• 1,030 J
• 0 J

7. The momentum of a 0.25 kg baseball thrown at 10 m/s is:

• a. 2.5
• b. 0
• c. 0.25
• d. 25

8. What is the impulse felt by a person who is hit with 600 N of force over 4 seconds?

• a. 150
• b. 0
• c. 10000
• d. 2400

9. What is the change in velocity of a car that goes from 10 m/s to 40 m/s?

• a. 0 m/s
• b. 10 m/s
• c. 40 m/s
• d. 30 m/s

10. What is the force felt by a 70 kg man if he is going 10 m/s and slams on his brakes and brings his car to a stop? The time it takes him to stop is 2.5 seconds.

• a. 180
• b. 380
• c. 480
• d. 280

11. A Black ball (8 kg) is traveling to the right at a velocity of 3 m/s. It hits a White ball (4 kg) traveling to the left at a velocity of 7 m/s. What is the momentum of the White ball before they hit (remember for these next five problems that right is positive and left is negative).

• a. -24
• b. -2.67
• c. 0
• d. -28

12. What is the momentum of the Black Ball before they hit?

• a. 2.67
• b. 2
• c. 0.57
• d. 24

13. What is the total Momentum of the collision?

• a. -2.1
• b. 2.1
• c. 4
• d. -4

14. Which way would the White ball be traveling after it hits the Black ball?

• a. not moving
• b. they exploded
• c. left
• d. right

15. After they hit, the White ball is moving at 5 m/s. What is the new velocity of the Black ball?

a. 5 m/s

b. 7m/s

c. 6m/s

d. -3 m/s