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

Options

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

Answer

B

Explanation

According to the law of conservation of angular momentum `30 xx 0=18 xx 6 + 12 xx v rArr v= -9m//s`
Negative sign indicates that both fragments move in the opposite directions
K.E. of `12kg =½ mv^(2) = ½ xx 12 xx 81 = 486J`