momentum notes

momentum notes - Transcript

Chapter 6 Momentum and Collisions
The linear momentum of an object of mass m moving with a velocity v is defined as the product of the mass and the velocity

Momentum is a vector and therefore has components

The time rate of change of momentum of an object is equal to the net force acting on the object

Impulse momentum theorem The impulse of the force acting on an object is equal to the change in momentum of that object

Example In a crash test a 1 5 x 103 kg car collides with a wall The car starts with an initial velocity of 15 m s and ends with a final velocity of 2 6 m s If the collision lasts for 0 15 seconds find the impulse on the car due to the collision and the magnitude and direction of the average force acting on the car
Momentum is conserved
When no external forces act on a system consisting of two objects that collide with each other the total momentum of the system before the collision is equal to the total momentum of the system after the collision

Example A baseball player uses a 50 0 kg pitching machine to practice in the winter The machine is placed on an icy mound with negligible friction The machine fires a 0 15 kg baseball with a speed of 36 m s What is the recoil speed of the machine