1. Momentum The property of moving object has that makes it difficult to stop. (technically, product of mass and velocity) Formula: p = mv

2. Impulse When a force acts on an object, it’s velocity changes, therefore changing its momentum J = Ft = change in p = mv (Impulse = change in momentum)

3. Examples A 5 kg mass moving with a vector of 8 m/s east has an impulse applied to it which causes its velocity to change to 20 m/s East. Find the Impulse. How long would it take for a net upward force of 100N, to increase the speed of a 50kg object from 100 m/s to 150 m/s.

4. Conservation of Momentum Total Momentum Before = Total Momentum After m 1 v 1 + m 2 v 2 = m 1 v 1 + m 2 v 2 **Remember to use +/- for direction of velocities!!**

5. Conservation of Momentum Collisions –Elastic: objects collide and bounce apart –Inelastic: Objects collide and stick together Examples: –1. A 3 kg object traveling 6 m/s east has a perfectly elastic collision with a 4 kg object traveling 8 m/s west. After the collision, the 3 kg object will travel 10 m/s west. a) What was the total momentum before the collision? b) What is the total momentum of these objects after this collision? c) What velocity will the 4 kg object have after the collision?

6. Examples (cont’d) –2. A 10 kg cart moving with a velocity of 10 m/s East collides and attaches itself to a 10 kg cart moving at a velocity of 50 m/s west. a) Find the total momentum before the collision b) Find the total momentum after the collision c) What is the velocity of the attached carts after the collision? –3. What is the magnitude of the total momentum of these carts?