Question

If g is the acceleration due to gravity on the earth’s surface, the gain in the potential energy of an object of mass m raised from the surface of earth to a height equal to the radius of the earth R, is

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

Gravitational potential energy of a body at height h from the earth surface$=\frac{mgh}{1+\frac{h}{R}}$
gain in potential energy $=\frac{mgh}{1+\frac{h}{R}}=\frac{mgR}{1+\frac{R}{R}}=\frac{1}{2}mgR$

[As h = R (given)]