# physics

posted by
**ck**
.

The period of a satellite is the primary way that the mass of planets is determined. The equation used for this calculation uses the fact that gravity of the planet provides the centripetal force to keep the satellite in orbit. The distance from the Earth to the Moon is 3.8 x 108 m and the period of the moon is approximately 27.3 days. Use the formula derived for this purpose to calculate the mass of the Earth.2 r3 )/(G T2 ) where T is the period of the moons orbit rotation.