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)