# Energy released in explosion

1. Jun 20, 2004

### PhysicsBeginner

Hi everyone, i've been trying to do this question here but i'm stuck on the last part:
A 23.0 kg body is moving with a speed of 25.0 m/s in the direction of the positive x axis when, owing to an internal explosion, it breaks into three parts. One part, which has a mass of 5.50 kg, moves away from the point of explosion with a speed of 65.0 m/s in the direction of the positive y axis. A second fragment, with unknown mass, moves with a speed of 125 m/s, at an angle of 15.0 degrees below the positive xaxis. The third fragment is observed to move in the direction of the negative x axis.

How much energy was released in the explosion?

I have found all the unknown masses and velocities and i am using the kinetic energy of a system equations which are the sum of the kinetic energy associated with the motion of the center of mass and the kinetic energy associated with the motion of the particles of the system. But i'm getting the wrong answer.

Can someone help me out?

2. Jun 20, 2004

### Staff: Mentor

Show your work and we'll take a look.

If you've correctly found the KEs of each piece after the collision, just add them up and subtract the initial KE. That will be the energy released.