$A$ body is falling under gravity from rest. When it loses a gravitational potential energy by $U,$ its speed increases to $v.$ The mass of the body shall be

$A$ bullet of mass $200\,g$ having initial kinetic energy $90\,J$ is shot inside a long swimming pool as shown in the figure. If its kinetic energy reduces to $40\,J$ within $1\,s$,the minimum length of the pool the bullet has to travel so that it completely comes to rest is $.....m$.

$A$ ball of mass $2\,kg$ and another of mass $4\,kg$ are dropped together from a $60\,ft$ tall building. After a fall of $30\,ft$ each towards the earth,their respective kinetic energies will be in the ratio of:

Two masses of $1 \,g$ and $4 \,g$ are moving with equal kinetic energies. The ratio of the magnitudes of their linear momenta is

If the momentum increases by $0.01\%$,what is the percentage increase in kinetic energy (in $\%$)?

If momentum is increased by $20 \%$, then kinetic energy increases by (in $\%$)