# Inelastic collisions

1. Jul 20, 2011

### fa08ti

in a movie stunt, a 65 kg skier starts from a rest postion at the top of a hill 30 m high. she slides down the hill to the bottom, where she collides with a 45 kg stationary skier. the collision is completely inelastic. find the fiinal velocity of the skiers.

ATTEMPT.
i know i have to use
m1v1+ m2v2= (m1+m2)v

but i'm not sure about what values to use. and why am i given the height?

2. Jul 20, 2011

### PhanthomJay

The height will determine the speed of the 65 kg skier as she reaches the bottom of the hill just before colliding with the stationary skier. What equation should you use to get that speed?

3. Jul 20, 2011

### fa08ti

the only equation for speed i can think of is distance/time

4. Jul 20, 2011

### dmriser

The skier at the top of the hill has potential energy which all gets turned into kinetic energy at the bottom. This is why the height of the hill is given.

5. Jul 20, 2011

### cupid.callin

if you are uncomfortable with energy method ... you can also do it with simple kinematics.

Tell me if you need help