A bomb of mass `30 kg` at rest explodes into two pieces of mass `18 kg` and `12 kg`. The velocity of mass `18 kg is 6 m//s`. The kinetic energy of the other mass is

Options

A. 324 J
B. 486 J
C. 256 J
D. 524 J

Answer

B

Explanation

From conservation of linear momentum
`m_(1)v_(1)+m_(2)v_(2)=0`
`v_(2)=((-m_(1))/(m_(2)))v_(1)=((-18)/(12))6=-8ms^(-1)`
`K.E.(1)/(2)m_(2)v_(2)^(2)=(1)/(2)xx12xx19^(2)=486J`