Question

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

Answer 1

$\frac{GM}{(R+h{)}^2}=\frac{6.67\times {10}^{-11}\times 7.4\times {10}^{22}}{(1740+10000{)}^2\times {10}^6}=\frac{6.67\times 7.4\times {10}^{11}}{(1740+{1000}^2\times {10}^6)}=\frac{6.67\times 7.4\times {10}^{11}}{2740\times 2740\times {10}^6}=0.65m/s^2$