Q: A rocket is launched vertically from the surface of earth with an initial velocity *v*. How far above the surface of earth it will go ? Neglect the air resistance.

(a) $ \displaystyle R(\frac{2 g R}{v^2}-1)^{-1/2} $

(b) $ \displaystyle R(\frac{2 g R}{v^2}-1) $

(c) $ \displaystyle R(\frac{2 g R}{v^2}-1)^{2} $

(d) $ \displaystyle R(\frac{2 g R}{v^2}-1)^{-1} $

Ans: (c)