What is the acceleration at a point 20,000 km above the earth’s surface?

Question

Can I have complete solution please. Thank you so much in advance! :)

Answer 1

mg = GmM/r²; g = GM/r². g_h = GM/(r + h)². g_h = gr²/(r + h)². Here r is radius of earth , r = 6378 km

g_h = 9.81m/s²·6378²/(6378 + 20000)² = 0.574 m/s².