Find the ratio of momentum of the two bodies $A$ and $B$ of masses $m$ and $4m$ respectively,moving with the same velocity $v$.

$(a)$ How much momentum will an object of mass $10 \ kg$ transfer to the floor if it falls from a height of $0.8 \ m$? $(g = 10 \ m s^{-2})$
$(b)$ Explain why it is difficult for a fireman to hold a hose,which ejects a large amount of water at a high velocity.

Quick sand consists of very smooth and tiny grains of sand. What would happen if a man or a heavy animal steps over a patch of such sand in a desert?

The velocity versus time graph of a ball of mass $50 \, g$ rolling on a concrete floor is shown in the figure. Calculate the acceleration and the frictional force exerted by the floor on the ball.

$A$ water tanker filled up to $2/3$ of its height is moving with a uniform speed. On sudden application of the brake,the water in the tank would

$A$ player catching a moving ball moves his hand backwards. Why?