Question

If the gravitational potential due to the earth on its
surface is assumed to be zero, then gravitational
potential at height 2R from surface will be
(R.: Radius of the earth; g: acceleration due to
gravity on earth surface)
​

Answer 1

Answer:

-GmM/3R

Explanation:

Since, the gravitational potential due to earth on its surface is given in the question as zero. So, U1=0. The potential at the surface would have been given as U=-GmM/R, but in this case it is 0.

When the body is taken to a distance 2R from the surface so, the radius becomes (R+2R). So, the gravitational potential is U2=-GmM/3R. Hence, the change in the potential energy will be given as U2-U1. Which will be equal to  -GmM/3R -0 which on solving we will get that -GmM/3R.