# Homework Help: Energy of Explosion

1. Oct 14, 2007

### sheri1987

1. The problem statement, all variables and given/known data

A 16 kg asteroid is traveling through space with velocity v = 180 m/s when it breaks up into three equal pieces. One piece is left at rest, and a second one continues with the same velocity. What was the energy of the explosion (in Joules)?

2. Relevant equations

E=1/2mv^2

3. The attempt at a solution

I tried using the kinetic energy equation cause it wants me to find energy, yet I'm pretty sure this is wrong. How do I go about solving this?

2. Oct 14, 2007

### dynamicsolo

I notice that the statement of the problem says nothing about the third piece. Have you had conservation of linear momentum yet? You are going to need to know what that third fragment is doing, in order to have a proper inventory of kinetic energy...

3. Oct 15, 2007

### sheri1987

No, I have not had that yet.

4. Oct 15, 2007

### Gear300

Use conservation of linear momentum. Either that, or, I suppose, the conservation of mechanical energy. You could say that the meteor had a kinetic energy and then say that work was done on it (causing the explosion). Essentially, it comes out to something like this:
i = initial, f = final, KE = Kinetic Energy, Wnc = Work (nonconservative), 1,2,3 respond to the 3 masses after the explosion.
KEi + Wnc = KEf1 + KEf2 + KEf3
Using the above equation, find Wnc for the energy of the explosion (I'm actually just another student, so it is possible that there might be some error in there. However, it looks ok)

Last edited: Oct 15, 2007