$A$ book of mass $2 \, kg$ is sliding with a constant velocity of $4 \, m s^{-1}$ on a frictionless horizontal table. What is the force required to keep the object moving with the same velocity (in $, N$)?

$A$ block is supported by a cord $A$ from a rigid support,and another cord $B$ is attached to the bottom of the block. If you give a sudden jerk to $B$,it will break. But if you pull on $B$ steadily,$A$ will break. Why?

State whether the following statement is true or false:
Force may or may not produce any motion in a body.

$m_{1}$ and $m_{2}$ masses of two blocks are connected by a light spring on a smooth horizontal surface. The two masses are pulled apart and then released. Prove that the ratio of their acceleration is inversely proportional to their masses.

If a body is in motion,is it necessary that it is being acted upon by a force?

Why does friction not roll a ball backward if no external force is pushing or pulling it?