A body of mass ' ${m}$ ' dropped from a height ' ${h}$ ' reaches the ground with a speed of $0.8 \sqrt{{gh}}$. The value of workdone by the air-friction is $.....\,{mgh}$

If the increase in the kinetic energy of a body is $22\%$, then the increase in the momentum will be ........... $\%$

Two bodies of unequal mass are moving in the same direction with equal kinetic energy. The two bodies are brought to rest by applying retarding force of same magnitude. How would the distance moved by them before coming to rest compare ?

A block of mass $1\,kg$ slides on a rough horizontal surface. If the speed of the block decreases from $10\,m/s$ to $8\,m/s$ , the thermal energy developed in this process .................. $\mathrm{J}$

A time dependent force $F = 6t$ acts on a particle of mass $1\ kg$. If the particle starts from rest, the work done by the force during the first $1$ secand will be ............... $\mathrm{J}$

A particle is moving in a circular path of radius a under the action of an attractive potential $U = - \frac{k}{{2{r^2}}}$ Its total energy is