1. Impulse and Momentum Section 9.1
Physics

2. 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. Impulse and Momentum Tennis serve: Before During After
The change in the ball’s
velocity is caused by a force.

4. Impulse and Momentum The force changes over time.
Just after contact is made, the ball is squeezed, the racket strings are stretched, and the force increases.

5. Changing Forces

6. Impulse and Momentum
The force on the ball is 1000 times greater than the weight of the ball.
We can find the impulse and momentum the ball undergoes during a serve by using an equation.

7. Impulse and Momentum
Impulse: The product of the average net force exerted on an object and the time interval over which the force acts.
Momentum: A measure of the motion of a body equal to the product of its mass and velocity.
Angular
Linear

8. Impulse-Momentum Theorem
Derived from Newton’s Laws of Motion.
Impulse = FΔt
Momentum (p) = mv
FΔt = p2 – p1

9. Applying the Impulse-Momentum Theorem
How can we use the impulse-momentum theorem to save lives?
Air bags.
Crumple zones.
Buffer barrels around bridge pylons.

10. Saving Lives
The less force that must be absorbed by the driver/person, the higher chance they will survive the impact.
We can reduce the force by increasing the time over which the impact occurs.
F = m(Δv/Δt)

11. Practice Problems Pg
1-6