Q 11-07-064JEE MainJEE Main 2024 (6 Apr, Shift 1)Easy
To project a body of mass $m$ from the earth's surface to infinity, the required kinetic energy is (assume the radius of earth is $R_E$ and $g$ = acceleration due to gravity on the surface of earth)
Answer: (C) $mgR_E$
The kinetic energy must cancel the potential energy $-\dfrac{GMm}{R_E}$:
$$K = \frac{GMm}{R_E} = \frac{gR_E^2m}{R_E} = mgR_E$$
Solution by Sreeraj P, M.Sc Physics