1. Kepler’s Laws (see video)
The square of the period of a planet’s orbit is directly proportional to the cube of its mean distance from the Sun.

2. Satellite motion
If an orbiting satellite had a period of 24 hours, and you saw it overhead at, say am, when would you next see it overhead?
Geosynchronous

3. Satellite motion
If you wanted the satellite to remain directly overhead (i.e. above a fixed point on the Earth) at all times (not just once per day) where on the Earth would you have to be?
Geostationary

4. Geostationary Satellites
Period of orbit must be the same as the Earth
Orbit must be directly above the equator
Must rotate in the same sense as the Earth

5. Gravitational Field vs Electric Field
Definition of field strength
Units
Uniform field
Vector forces