1. Linear Momentum
Physics
Mr. Berman

2. Linear Momentum, p p= m v Momentum is a vector.
Momentum is a vector.
The direction of momentum is the same as the direction of the velocity of the object.
Unit: kg m/s or N s
“Inertia in Motion”

3. Question 1:
What has more momentum, a truck at rest or a pebble moving down a hill at 1m/s?

4. Question 2
How can you change the momentum of an object?

5. Impulse =
Change in Momentum
Impulse = p = m v = Ft

6. Problem 1
Starting with Newton’s second law, show that for a constant force, p = m v = Ft .

7. For a given change in velocity, p is constant :D
p= F t
To reduce the force of impact, increase the time of impact.

8. Question 3:
How do you have a better chance of winning in a water balloon toss contest?

9. Question 4:
Why does a boxer “roll with the punches”?

10. Question 5:
Why should you follow through in a serve when playing tennis, or when hitting a baseball?

11. Problem 2
A ball at rest has a mass 0.5kg and
is kicked with a force of 40N. The
impact lasts 0.2s. Find:
The change in momentum of the ball.
The final velocity of the ball. Answer: a) 8 Ns, b)16m/s

12. Problem 3
A football player of mass 130kg travelling at 12.0m/s collides with another player and comes to rest in 0.90s. What was the force of impact?
Answer:1,733N

13. Impulse is the area under the curve in a graph of F vs t.

14. Some Engineering Applications

15. Question 6
Why are airbags used?

16. M A R S E
X P L O R A T I O N

17. MARS LANDER AIR BAGS

18. Rover Exits the Lander

19. Applications in Engineering Household Items

20. MILK BOTTLES

21. THE EGG CARTON