If the speed of the 1rst fagment is 6.3m/s,find the internal energy of the explosion.?

Question

An object initially at rest explodes in two fragments of masses 4.8kg & 1.8kg that move in diametrically opposite directions.

Answer 1

Before...Kaboom! Aafter

there is a change in momentum P
before and after

Before P=0
P after = m1V1-m2V2
so
V2=V1(m1/m2)=
V2=6.3m/s( 4.8kg /1.8kg )=30.8m/s

Answer 2

The Seductive Stargazer is correct however he did not finish the work and the V2=16.8m/s
The total energy of the explosion equal to the sum of kinetic energies.
Et=Ke1+Ke2
Et=0.5 m1v1^2+ 0.5 m2v2^2
Et=.5(4.8(6.3)^2 +1.8 ( 16.8 )^2)=
Et=.5(698)=
Et=349 Joules