Question

A stationary bomb explodes into two parts of masses $3kg$ and $1kg$. The total KE of the two parts after explosion is $2400J$. The KE of the smaller parts is :

• A. 600 J
• B. 1800 J
• C. 1200 J
• D. 2160 J

Answer 1

Answer: (B)

1800 J

$KE=\frac{p^2}{2m}$

$\frac{P^2}{2\left(1\right)}+\frac{P^2}{2\left(3\right)}=2400$ or $P^2=2400\times \frac{3}{2}$ and $\frac{P^2}{2m}=\frac{2400\times 3}{4}=1800J$