1. Momentum and Its Conservation

2. Impulse and Momentum Objectives
Compare the system before and after an event in momentum problems
Define the momentum of an object
Determine the impulse given to an object
Recognize that impulse equals the change in momentum of an object

3. Momentum What is momentum?
The Seattle Seahawks had momentum entering the final weeks of the season…
Anything that is moving
has momentum
Depends on what?

4. Momentum Momentum = mass * velocity
In physics, the symbol for momentum is “p”
sssooo…
p = m * v
SI units are kg·m/s
Which has more momentum, a supertanker tied to a dock or a raindrop falling?

5. Momentum Determine the momentum of a ...
60-kg halfback moving eastward at 9 m/s.
60 x 9 = 540 kg·m/s east
1000-kg car moving northward at 20 m/s.
1000 x 20 = 20,000 kg·m/s
40-kg freshman moving southward at 2 m/s.
40 x 2 = 80 kg·m/s

6. Impulse and Momentum Impulse = Change in momentum Impulse
The product of the average net force exerted on an object and the time interval over which the force acts
N•s

7. Real Life Applications..
Sports…
Follow-through!
Gymnastics Mats
Cars…
Airbags!
Before airbags….
Bumpers
Eggs…
Jumping…
Knees
Shoes

8. Review
Can a bullet have the same momentum as a truck?

9. The Conservation of Momentum
Objectives
Recognize the conditions under which the momentum of a system is conserved
Apply conservation of momentum to explain the propulsion of rockets
Solve conservation of momentum problems in two dimensions by using vector analysis

10. The Law of Conservation on Momentum
The total momentum of two objects before a collision is equal to the total momentum of the two objects after the collision.
P(before) = P(after)

11. Two Particle Collisions
Inelastic collisions
mAvA1 + mB1vB1 = mAvA2 + mBvB2