Question

A sphere of mass $40$kg is attracted by a second sphere of mass $60$kg with a force between them is equal to $4mg$. If $G=6\times {10}^{-11}$N$m^{2}k{g}^{-2}$, calculate the distance between them. Acceleration due to gravity $=10m{s}^{-2}$.

Answer 1

$F=\frac{G{m}_1{m}_2}{r^2}=>40\times 10=\frac{6.67\times {10}^{-11}\times 60\times 40}{r^2}=>r^2=0.00002m$