## Essential University Physics: Volume 1 (4th Edition)

We use the given equation to find: a) $a = \frac{GM_E}{R_E^2} = \frac{6.67\times 10^{-11}\times5.67\times10^{24}}{(6.37 \times 10^6)^2} = 9.81 \ m/s^2$ b) $a = \frac{GM_E}{r^2} = \frac{6.67\times 10^{-11}\times5.67\times10^{24}}{(6.37 \times 10^6+380 \times 10^3)^2} = 8.74\ m/s^2$