delta P - Unit 7

In this unit, we learned about momentum. In order to find momentum, you must know the mass and velocity. To find the change in momentum, you will have to know the average force and change in time. To be put simply, momentum is just inertia in motion. When we look at momentum between two objects, some things never change. If the two colliding objects have different masses, they will still have the same force of impact, the impulses would be the same, the changes in momentum would be the same (same thing as impulse, changes in momentum and impulse are two interchangeable words), however, the speeds of the two objects will be different (because mass is inversely related to velocity).

Here is a sample problem: A 50kg man is running with a velocity of 10m/s north onto a 1000 kg car. When the man is in the car, the velocity is 15 m/s north. What was the velocity of the car after the man jumped on it?

Equation: MboyiVboyi + McariVcari = (Mboy + Mcar) Vf

50kg(10m/s) + 1000kg(15m/s) = (50kg+1000kg) Vf

500 + 15000 = 1050Vf

15500 = 1050vf

Vf = 14.76 m/s