A body weighs 72 N on the surface of the earth. What is the gravitational force on it, at a height equal to half the radius of the earth?

The work done to raise a mass m from the surface of the earth to a height h, which is equal to the radius of the earth, is :

A body weight 200 N on the surface of earth. How much will it weight half way down to the centre of the earth?

The kinetic energies of a planet in an elliptical orbit about the Sun, at positions A, B and C are K_A, K_B and K_C, respectively. AC is the major axis and SB is perpendicular to AC at the position of the Sun S as shown in the figure. Then