Q. Two bodies of masses $0.1\ kg$ and $0.4\ kg$ move towards each other with the velocities $1\ m/s$ and $0.1\ m/s$ respectively, After collision they stick together. In $10\ sec$ the combined mass travels
A) $120\ m$
B) $0.12\ m$
C) $12\ m$
D) $1.2\ m$
Explanation
(d) Velocity of combined mass, $v = \frac{m_{1}v_{1} - m_{2}v_{2}}{m_{1} + m_{2}}$
$= \frac{0.1 \times 1 - 0.4 \times 0.1}{0.5} = 0.12\ m/s$
$\therefore$ Distance travelled by combined mass
$= v \times t = 0.12 \times 10 = 1.2\ m$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.