Question

A bomb of mass $9kg$ explodes into $2$ pieces of mass $3kg$ and $6kg$. The velocity of mass $3kg$ is $1.6m/s$, the kinetic energy of mass $6kg$ is :

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

Answer 1

The correct option is C $1.92J$

Using conservation of linear momentum, total momentum of the bomb before and after explosion remains the same.

$0=3\times 1.6+6v$

$v=0.8m/s$

Kinetic energy of mass $6kg$ is:

$\frac{1}{2}{mv}^2=\frac{1}{2}\times 6\times {0.8}^2$

$=1.92J$