Question

The gravitational potential energy of a body at a distance “r” from the centre of the earth is V. Its weight at a distance “2r” from the centre of the earth is _____

(a) V/r

(b) V/4r

(c) V/2r

(d) 4V/r

Answer 1

Right option is (b) V/4r

Best explanation: Gravitational potential energy (V) at a distance “r”;

V = -(G*M*m)/r

Gravitational force at a distance “r” = -(G*M*m)/r^2

 = V/r

Gravitational force at a distance “2r” = -(G*M*m)/4r^2

 = V/4r.