Q. A body moving with a velocity v, breaks up into two equal parts. One of the part retraces back with velocity$\ v.$Then, the velocity of the other part is
A) $v$, in forward direction
B) 3 $v$ in forward direction
C) $v$, in backward direction
D) 3 $v$ in backward direction
Explanation
(b) Let $M$be the mass of body moving with velocity v and m be mass of each broken part, velocity of one part which retraces back is v and that of second part is v’.
Momentum before breaking=momentum after breaking
$Mv = m( - v) + mv'$
Or $v^{'} = \frac{Mv + mv}{m}$
Since, M=2m,therefore
$v^{'} = \frac{(2m + m)v}{m} = 3v$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.