Explosion of one mass into three

[haroldham]

Homework Statement

A 4.2 kg object, initially at rest, "explodes" into 3 objects of equal mass. Two of these are determined to have velocities of equal magnitudes (5.0 m/s) with directions that differ by 90 degrees. How much kinetic energy was released in the explosion? (that is what is the energy of the three object systems after the explosions)

Homework Equations

To be honest, my teacher did not cover this in class so I'm naked in the dark on this one.

The Attempt at a Solution

Since they are at 90 degrees to each other, one would be 5 j m/s and the other would be 5 i m/s. I am not sure where to go from there or where the third factors in.

 

[LowlyPion]

Since the center of mass remains the same from conservation of momentum, then first figure the velocity of the third object. (Happily you can because you know the mass of all 3 pieces are equal.)

Then you know how much KE each piece has since you know their masses and velocities.

 

[haroldham]

Ok, thank you so much. I undertand.

 

[haroldham]

Did you get 103.5 J?

 

[LowlyPion]

Perhaps you should show your calculation?