Question

A particle of mass $10g$ is kept on the surface of a uniform sphere of mass, 100kg and radius 10 cm be done against the gravitational force between them to take the particle far away from the sphere $(G=6.67\times {10}^{11}N{m}^2/kg$)

Answer 1

Work done,

$W=?$

$U=Uf-Ut=0–[-GMm/R]$

$W=6.67\times 10-11\times 100/0.1\times 10/1000$

$=6.67\times {10}^{-10}J$.