Q. A space craft of mass M and moving with velocity v suddenly breaks in two pieces of same mass m. After the explosion one of the mass m becomes stationary. What is the velocity of the other part of craft?
A) $\frac{Mv}{M - m}$
B) V
C) $\frac{Mv}{m}$
D) $\frac{M - m}{m}v$
Explanation
(c) Let velocity of masses after explosion be $v_{1}and\ v_{2},\ $then from law of conservation of momentum, we have
Momentum before explosion = Momentum after explosion
$MV = m_{1}v_{1} + m_{2}v_{2}$
${Given\ \ m}_{1} = m_{2} = m,v_{2} = 0\ ,$
$\therefore\ Mv = mv_{1} + m \times 0$
$\ \Rightarrow \ v_{1} = \frac{Mv}{m}.$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.