Q. Two bodies of masses 2 kg and 4 kg are moving with velocities 20 $ms^{- 1}$ and 10 $ms^{- 1}$ towards each other due to mutual gravitation attraction. What is the velocity of their centre of mass?
A) 5 $ms^{- 1}$
B) 6$\ ms^{- 1}$
C) 8$\ ms^{- 1}$
D) Zero
Explanation
(d) Since net force acting on the system is zero, hence position of centre of mass of the system remains unchanged $ie$, velocity of the centre of mass is zero
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.