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

Two bodies of masses m and $2m$ have same momentum. Their respective kinetic energies ${E_1}$ and ${E_2}$ are in the ratio

A body of mass $2\, kg$ is thrown up vertically with K.E. of $490$  joules. If the acceleration due to gravity is $9.8$$m/{s^2}$, then the height at which the K.E. of the body becomes half its original value is given by ………… $\mathrm{m}$

A body of mass $(4m)$ is lying in $x-y$ plane at rest. It suddenly explodes into three pieces. Two pieces, each of mass $(m)$ move perpendicular to each other with equal speeds $(v).$ The total kinetic energy generated due to explosion is…………….. $mv^2$

A body of mass $10\,kg$ at rest is acted upon simultaneously by two forces $4 \,N$ and $3\,N$ at right angles to each other. The kinetic energy of the body at the end of $10 \,sec$ is ………….. $\mathrm{J}$