Question

If the potential energy of a body at a height h from the surface of the earth is `(mgR)/(2)`, then
A. h = 2R
B. `h = (R )/(2)`
C. `h = (R )/(3)`
D. h = R

Answer 1

Correct Answer - D
`P.E.=-(GMm)/(R+h)=(-gR^(2)m)/(R+h)`
In magnitude, `(gR^(2)m)/(R+h)=(1)/(2)mgR`
`therefore R + h=2R " " therefore h = R`