Question

Two bodies of equal mass,m, with equal velocities,v, moving in opposite directions collide. The resultant velocity of the combination is?

Answer 1

Momentum of the system before collision is $p_1=mv-mv=0$ (Since the bodies are moving in opposite direction with equal speed.

According to the law of conservation of momentum, momentum after collision is equal to momentum before collision.

Therefore, momentum after collision, $p_2=p_1=0$.

The resultant velocity of the combination, $V=\frac{p_2}{2m}=\frac{0}{2m}=0$.

Thus, the resultant velocity of the combination will be zero.