# Finding kinetic energy consevered after collision

1. Jan 28, 2015

### qwerty5050

1. The problem statement, all variables and given/known data
2 cars of equal mass and travelling in opposite directions on a wet and slippery road collide and lock together after impact. Neither car brakes before the collision. The tangled wreck moves off in an easterly direction at 5 m/s immediately after the collision. if one car was travelling due west at 20 m/s immediately before the collision and the other at 30 m/s.
What fraction of the initial kinetic energy as conserved during the collision?

2. Relevant equations
Ek=1/2mv^2 - this is the only equation i know that has to do with kinetic energy
3. The attempt at a solution
I have no idea what i have to do

Last edited: Jan 28, 2015
2. Jan 28, 2015

### Staff: Mentor

Start by listing equations that you think may be relevant. Perhaps that will trigger an idea or two for an attempt.

3. Jan 28, 2015

### qwerty5050

I've been doing that but I'm still not sure what to do.

4. Jan 28, 2015

### Staff: Mentor

Hmm. You haven't posted any, so we can't tell if you're on the right track or not.

The topic is kinetic energy. What equations do you know pertaining to kinetic energy?

5. Jan 30, 2015

### Suraj M

Try to think of things that remain constant during the given collision. Any law you know that might apply. Think!