A light particle moving horizontally with a speed of $12\ m/s$ strikes a very heavy block moving in the same direction at $10\ m/s$. The collision is one-dimensional and elastic. After the collision, the particle will
Move at $2\ m/s$ in its original direction
Move at $8\ m/s$ in its original direction
Move at $8\ m/s$ opposite to its original direction
Move at $12\ m/s$ opposite to its original direction
$Assertion$ : If collision occurs between two elastic bodies their kinetic energy decreases during the time of collision.
$Reason$ : During collision intermolecular space decreases and hence elastic potential energy increases.
Body of mass $M$ is much heavier than the other body of mass $m$. The heavier body with speed $v$ collides with the lighter body which was at rest initially elastically. The speed of lighter body after collision is
A bullet when fired at a target with a velocity of $100\,\,m/sec$ penetrates one metre into it. If the bullet is fired at a similar target with a thickness $0.5\,\,metre,$ then it will emerge from it with a velocity of
Two equal masses ${m_1}$ and ${m_2}$ moving along the same straight line with velocities $+ 3 \,m/s$ and $-5\, m/s$ respectively collide elastically. Their velocities after the collision will be respectively
The quantities remaining constant in a collision are