Concept:Conservation of linear momentum applies because the body is initially at rest.
Explanation:Initial momentum of the stationary body is zero.
After the explosion, the two parts move in opposite directions.
By conservation of momentum:
M1V1=M2V2This gives:
V2V1=M1M2Kinetic energy of a body is:
K=21mv2So the ratio of kinetic energies is:
K2K1=21M2V2221M1V12Simplifying:
K2K1=M2M1(V2V1)2Substitute the velocity ratio:
K2K1=M2M1(M1M2)2Hence:
K2K1=M1M2Answer:The ratio of their kinetic energies is
M1M2.
Therefore, the correct option is
Option B.