Question

A bomb of mass 9 kg explodes into two pieces of mass 3kg and 6kg . The velocity of mass 3kg is 16 m/s . The K.E of mass 6kg is :

• A. 96 J
• B. 768 J
• C. 384 J
• D. 192 J

Answer 1

Answer: (D)

Given mass of the bomb$=M=9㎏$

Initial value of bomb$=0㎧$

Mass of smaller fragment$=3㎏\to m_1$

Mass of bigger fragment$=6㎏\to m_2$

P(just after explosion)=P (just before explosion)

$m_1\times 11+m_2\times v=M\times 0$

$v=-8㎧$

Kinetic energy of mass $6㎏=\frac{1}{2}{m}_2{v}^2$

$=\frac{1}{2}\times 6\times 64$

$=192J$