The kinetic energy needed to project a body of mass m from the earth's surface to infinity is

(a) 1/4 mgR

(b) 1/2 mgR

(c) mgR

(d) 2 mgR.

4 views

1 Answers

(c) mgR.

EXPLANATION: 

The kinetic energy should be equal to the gravitational potential energy K=U = GMm/R.  

Since g = GM/R² →GM =gR² 

Hence, K = gR²*m/R =mgR

4 views