Masses and radius of the earth and moon are M1, R1 and M2, R2 respectively. The distance between their centers is d. With what velocity an object of mass m should be projected from the mid-point between them so that it may escape?
(a) \(2\sqrt{\frac{G}{d}(M_1+M_2)}\)
(b)\(2\sqrt{\frac{2G}{d}(M_1+M_2)}\)
(c) \(2\sqrt{\frac{Gm}{d}(M_1+M_2)}\)
(d) \(2\sqrt{\frac{GM}{d}\frac{M_1+M_2}{R_1+R_2}}\)