Impulse & Momentum

Overview: Impulse & Momentum (Physicsclassroom.com)- very similar to lecture given in class on 1/19/2017.

First assignment: Momentum Master Equations

Second Assignment: Impulse & Momentum Practice Problems

WHAT IS A "MASTER EQUATION"? 
these assignments are asking you to manipulate the conservation of momentum equation (m1v1+m2v2 = m1v'1 + m2v'2) so that any variables that can be crossed off or simplified based on the initial and final conditions. 

For example,  
Write a master equation for this scenario:
2 carts have equal mass.  One is pushed and collides with the second cart, which had been at rest.  
You don't know the actual mass or velocities, but you are to simplify the expression to create a 'master equation'.

m1v1 + m2v2 = m1v'1 + m2v'2
we can eliminate several parts of this expression because of the conditions outlined above.

before the collision:
the second cart is not moving before the first cart hits it, so, v2 is 0, so m2v2 is also 0.
the initial conditions can be simplified to:   m1v1

after the collision,
the carts stick together, so they have the same velocity.  v'1=v'2
they also have the same mass.  m1=m2 
so the after the collision side of this expression can be simplified from m1v'1 + m2v'2 
to 2mv'  (2x mass of cart 1 X final velocity).

The entire master equation for this collision is:
m1v1= 2m1v'