Question

Calculate the force of earth's gravity on a spacecraft 12,800 km (2 earth radii) above the earth's surface if its mass is 1050 kg .

Answer 1

The force of earth gravity on the space craft is 1.19 N

\begin{array}{c}

F = \frac{{GMm}}{{{{\left( {r + h} \right)}^2}}}\\

= \frac{{6.67 \times {{10}^{ - 11}} \times 6 \times {{10}^{24}} \times 1050}}{{{{\left( {\left( {6400 + 12800} \right) \times {{10}^3}} \right)}^2}}}\\

= 1.139\;{\rm{N}}

\end{array}$

Hence, the force of gravity on the space craft is 1.19 N.