Question

A bomb of mass 12 kg at rest explodes into two pieces of masses 4 kg and 8 kg. If the velocity of 8 kg mass is \( 6\,{ms}^{-1} \), then the kinetic energy of 4 kg mass is

• A. 248 J
• B. 326 J
• C. 124 J
• D. 288 J

Hint:

Use momentum conservation to find velocities in explosions, then apply kinetic energy formula.

Answer 1

The Correct Option is D

Initial momentum = 0
Let velocity of 4 kg mass be \( v \)
Using conservation of momentum: \( 4v = 8 \times 6 \Rightarrow v = 12\,{ms}^{-1} \)
K.E. = \( \frac{1}{2} \times 4 \times 12^2 = 288\,{J} \)