$A$ bullet of mass $20 \,g$ leaves a rifle at an initial speed $100 \,m/s$ and strikes a target at the same level with speed $50 \,m/s$. The amount of work done by the resistance of air will be ......... $J$.

State the importance of the work-energy theorem. Is the work-energy theorem a scalar or a vector?

$A$ body of mass $m$ slides down a smooth hemispherical surface of radius $r$. What will be its velocity at the bottom of the surface?

Explain the work-energy theorem.

$A$ bus moving on a level road with a velocity $v$ can be stopped at a distance of $x$ by the application of a retarding force $F$. The load on the bus is increased by $25\%$ by boarding the passengers. Now,if the bus is moving with the same speed and if the same retarding force is applied,the distance travelled by the bus before it stops is

$A$ body is released from a height of $30 \ m$ vertically downwards. The speed of the body at which potential energy is twice that of kinetic energy is (Acceleration due to gravity $= 10 \ m \ s^{-2}$)