Gravity supplies the centripetal force that holds a satellite in orbit. That single idea fixes the speed and the period at every radius. Drag the orbit out and back, and find the one radius where the period is exactly 24 hours.
MissionPredict how a satellite's speed and period change as you move it to a higher orbit.Streak 0Best 0
Compared with a low orbit, a satellite in a higher orbit (larger r) has:
orbital radius r10 × 10⁶ m
orbital speed v = √(GM / r)6.3 km s⁻¹
period T = 2π√(r³ / GM)2.8 h
field strength g = GM / r²4.0 N kg⁻¹
Earth as the central mass. The dashed ring marks the geostationary orbit, where T = 24 h and the satellite stays above one point on the Equator.