1. Created for CVCA Physics By Dick Heckathorn 18 November 2K + 4
Chapter 7
Created for CVCA Physics By
Dick Heckathorn
18 November 2K + 4

2. Table of Contents 3 Car into Car vs Car into Wall 6 VW and Cadillac
7 Jacko catching a ball
8 Jacko getting off ice
9 CD 7.1 page 29
18 CD 7.1 page 30

4. Consider the consequences of driving a car into a head on collision with an identical car traveling toward you at the same speed
– as opposed to colliding at the
same speed against a massive
concrete wall.

5. Which of these two situations would result in the greatest impact force?
a. Colliding with the approaching car
b. Colliding with the massive stationary wall
c. Both would have the same impact

6. If a Cadillac and a Volkswagen have a head-on collision, which car will experience the greatest force?
a. The Cadillac
b. The Volkswagen
c. Both the same

7. Jocko, who has a mass of 60 kg and stands at rest on the ice, catches a 20 kg ball that is thrown to him at 10 km/hr.
How fast does Jocko and the ball move across the ice?

8. A fully dressed person is at rest in the middle of a pond on perfectly smooth ice and must get to shore.
How can this be accomplished?

9. Concept Development page-29
1. A moving car has momentum.
If it moves twice as fast, its momentum is twice as much.

10. 2. Two cars, one twice as heavy as the other, moves down a hill at the same speed.
Compared to the lighter car, the momentum of the heavier car is twice as much.

11. 3. The recoil momentum of a gun that kicks is
more than
less than
the same as
the momentum of the bullet it fires.

12. 4. If a man firmly holds a gun when fired, then the momentum of the bullet is equal to the recoil momentum of the
gun alone
gun-man system
man alone

13. 5. The momentum of an unlucky bug is suddenly changed as it splatters onto the windshield
a. Compared to the force that acts on the bug, how much force acts on the bus?
more
the same
less

14. 5. The time of impact is the same for both the bug and the bus.
b. Compared to the impulse on the bug, this means the magnitude of the impulse on the bus is
more
the same
less

15. 5. Although the momentum of the bus is very large compared to the momentum of the bug,
c. the change in momentum of the bus, compared to the change of momentum of the bug is
more
the same
less

16. d. Which undergoes the greater acceleration?
bus
both the same
bug

17. abug mbus e. Which, therefore, suffers the greater damage? bus
both the same
bug
Why?
Fbus on bug = Fbug on bus
mbug abug = mbus abus
abug
mbus
mbug =
abus

18. Concept Development page-30
Before Collision
Granny’s mass
80 kg
Ambrose’s mass
3 m/s
Granny’s momentum
240 kg-m/s
Ambrose’s mass
40 kg
Ambrose’s momentum
0 kg
Total momentum
240 kg-m/s

19. After Collision
Granny’s speed
Decreases
Ambrose’ speed
Increases
Total momentum
240 kg-m/s
Total mass of both
120 kg
Speed
2 m/s