Phy53 Lect    		Dr. brown		28 Sep 2010

examples -- center of mass for continuous distribution

1. quarter circle "coat hanger"

2. non-uniform linear density bar of length L

momentum

conservation of momentum

examples

1. skaters push each other

2. moving skater runs into stationary skater

Impulse = area under F(t)

Average force = \frac{impulse}{\Delta t}

example
gun shoots N bb's per unit time at plate with spring so average force can be measured

Collisions -- inelastic and elastic

	using center of mass reference frame

example
bullet hits block and slides along rough surface a distance D

introduces K = \frac{p^2}{2m}