A bomb of mass `9 kg` explodes into `2` pieces of mass `3 kg` and `6 kg`. The velocity of mass `3 kg is 1.6 m//s`. The `K.E. of mass 6 kg` is

Options

A. 3.84 J
B. 9.6 J
C. 1.92 J
D. 2.92 J

Answer

C

Explanation

As the bomb initially was at rest therefore
Initial momentum of bomb = 0
Final momentum of system `= m_(1)v_(1)+m_(2)v_(2)`
As there is no external force
`therefore m_(1)v_(1)+m_(2)v_(2)=0 rArr 3xx1.6+6xx v_(2)=0`
velocity of 6 kg mass `v_(2)=0.8 m//s` (numerically)
Its kinetic energy `=(1)/(2)m_(2)v_(2)^(2)=(1)/(2)xx6xx(0.8)^(2)=1.92 J`