Q: Two A body starts from rest from a point distant r_{0} from the centre of the earth. It reaches the surface of the earth whose radius is R. The velocity acquired by the body is

(a) $ \displaystyle 2 G M \sqrt{\frac{1}{R}-\frac{1}{r_0}} $

(b) $\displaystyle \sqrt{2 G M(\frac{1}{R}-\frac{1}{r_0})} $

(c) $ \displaystyle G M \sqrt{\frac{1}{R}-\frac{1}{r_0}} $

(d) $ \displaystyle \sqrt{G M(\frac{1}{R}-\frac{1}{r_0})} $

Ans: (b)