Can someone pls help me. Need help really fast PLEASE Which idea did Ptolemy’s model use to explain why the planets appeared to move backward as they moved in their orbits?

The planets spun in epicycles.
The planets rotated on their axes.
The planets revolved around the Sun.
The planets were made of different materials.

Determine the time it takes for a satellite to orbit the earth in a circular "near-earth" orbit. the definition of "near-earth" orbit is one which is at a height above the surface of the earth which is small compared to the radius of the earth, so that you may take the acceleration due to gravity as essentially the same as that on the surface. does your result depend on the mass of the satellite?