A Projectile Is Launched from the Surface of a Planet $\left[\frac{4 G M R}{3 R}\right]^{1 / 2}$

Multiple Choice

A projectile is launched from the surface of a planet (mass = M, radius = R) . What minimum launch speed is required if the projectile is to rise to a height of 2R above the surface of the planet? Disregard any dissipative effects of the atmosphere.

A) $\left[\frac{4 G M R}{3 R}\right]^{1 / 2}$
B) $\left[\frac{8 G M R}{5 R}\right]^{1 / 2}$
C) $\left[\frac{3 G M R}{2 R}\right]^{1 / 2}$
D) $\left[\frac{5 G M R}{3 R}\right]^{1 / 2}$
E) $\left[\frac{G M}{3 R}\right]^{1 / 2}$