Q 11-07-177JEE MainJEE Main 2019 (10 Jan, Shift 1)Easy
A satellite is moving with a constant speed $v$ in circular orbit around the earth. An object of mass $m$ is ejected from the satellite such that it just escapes from the gravitational pull of the earth. At the time of ejection, the kinetic energy of the object is:
Answer: (B) $mv^2$
In orbit of radius $r$, $v^2 = \dfrac{GM}{r}$. To just escape, total energy must be zero:
$$K = \frac{GMm}{r} = mv^2$$
Solution by Sreeraj P, M.Sc Physics