The kinetic energy needed to project a body of mass $m$ from the earth surface (radius $R$) to infinity is (1) $\mathrm{mgR}/2$ (2) $2\mathrm{mgR}$ (3) $\mathrm{mgR}$ (4) $\mathrm{mgR}/4$
The kinetic energy needed to project a body of mass $m$ from the earth surface (radius $R$) to infinity is\\
(1) $\mathrm{mgR}/2$\\
(2) $2\mathrm{mgR}$\\
(3) $\mathrm{mgR}$\\
(4) $\mathrm{mgR}/4$