A 8.00 kg shell at rest explodes into two fragments, one with a mass of 2.00 kg and the other with a mass of 6.00 kg.

If the heavier fragment gains 130 J of kinetic energy from the explosion, how much kinetic energy does the lighter one gain?

3 answers

You have to find the velocity of the heavier fragment, then its momentum. The lighter fragment will have opposite momentum, from which you can find its velocity.
2 piece shell have same kinetic energy u can find one piece velocity by apply 1/2m(v)2 rule
The lighter one will gain 130j also because from calculations it will move with a velocity 3 times that of the larger mass...