A body of mass $5\, kg$ moving with a velocity $10\, m/s$ collides with another body of the mass $20\, kg$ at rest and comes to rest. the velocity of the second body due to collision is ............ $\mathrm{m}/ \mathrm{s}$

Two bodies having same mass $40\, kg$ are moving in opposite directions, one with a velocity of $10$$m/s$ and the other with $7\,m/s.$ If they collide and move as one body, the velocity of the combination is ........ $m/s$

Two masses ${m_A}$and ${m_B}$moving with velocities ${v_A}$and ${v_B}$in opposite directions collide elastically. After that the masses ${m_A}$and ${m_B}$move with velocity ${v_B}$and ${v_A}$respectively. The ratio $ \frac{m_A}{m_B} =$

$A$ bal $A$ collides elastically with another identical ball $B$ initially at rest $A$ is moving with velocity of $10m/ s$ at an angle of $60^o$ from the line joining their centres. Select correct alternative :

A ball of mass $'m'$ is released from the top of a smooth movable wedge of mass $'m'.$ When the ball collides with the floor,velocity of the wedge is $'v'.$ Then the maximum height attained by the ball after an elastic collision with the floor is :(Neglect any edge at the lower end of the wedge).

Body $A$ of mass $4 \;\mathrm{m}$ moung with speed $u$ collides with another body $B$ of mass $2\; \mathrm{m}$, at rest. The collision is head on and elastic in nature. After the collision the fraction of energy lost by the colliding body $A$ is