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

Answer

B

Explanation

According to law of conservation of linear momentum `m_(A) v_(A)= m_(B) v_(B)= 18 xx 6= 12 xx v_(B) rArr v_(B)= 9m//s`
K.E. of mass 12kg . `E_(B)= (1)/(2) m_(B)v_(B)^(2)`
`=(1)/(2) xx 12 xx (9)^(2)= 486J`