Question

Find the acceleration due to gravity of the moon at a point $1000km$ above the moon's surface. The mass of the moon is $7.4\times {10}^{22}kg$ and its radius is $1740km$.

Answer 1

Acceleration due to gravity at a height= $\frac{GM}{(R+h{)}^2}=\frac{6.67\times {10}^{-11}\times 7.4\times {10}^{22}}{(1740+1000{)}^2\times {10}^6}$
$=\frac{49.358\times {10}^{11}}{2740\times 2740\times {10}^6}$
$=\frac{49.358\times {10}^{11}}{0.75\times {10}^{13}}=65.3\times {10}^{-2}=0.65m/s^2$