Q. A shell of mass $10\ kg$ is moving with a velocity of $10\ ms^{- 1}$ when it blasts and forms two parts of mass $9\ kg$ and $1\ kg$ respectively. If the $1^{st}$ mass is stationary, the velocity of the $2^{nd}$ is
A) $1\ m/s$
B) $10\ m/s$
C) $100\ m/s$
D) $1000\ m/s$
Explanation
(c) $v_{1} = 10\ m/s$ ; $m_{1} = 10\ kg$
$v_{2} = 0$ ; $m_{2} = 9\ kg$
$v_{3} = v$ ; $m_{3} = 1\ kg$
According to conservation of momentum
$m_{1}v_{1} = m_{2}v_{2} + m_{3}v_{3}$
$10 \times 10 = 9 \times 0 + 1 \times v;$ $v = 100\ m/s$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.