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

It is required to increase the velocity of a scooter of mass $80 \ kg$ from $5 \ m s^{-1}$ to $25 \ m s^{-1}$ in $2 \ s$. Calculate the force required.

The velocity-time graph of a ball of mass $20 \ g$ moving along a straight line on a level ground is given below. How much force does the ground exert on the ball to bring it to rest?

$A$ sledge of mass $80 \, kg$ moves over the frozen surface of a lake with a velocity of $30 \, m s^{-1}$ and comes to rest in $5 \, s$. Find its negative acceleration and the frictional force between the lake and the sledge.

When a fast-moving horse stops suddenly,a careless rider falls in the forward direction. Give the reason for this.

$A$ 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