## A Level Physics Session

Gravitation | Waves and Interference | Magnetic Force | Photoelectric Effect |

# Gravitation

Hi Everyone,

Welcome to this session on gravitation. The following are two videos on this topic.

090 Newton's law of gravitation

091 Gravitational field strength

### Exercises

Please try these questions.- Suppose that a satellite always stays directly above the same spot on Earth’s equator.
Find the period of revolution of the satellite in SI units.
- Find its angular velocity.
- Using GMm/r² and mω²r, write down an equation relating the gravitational and centripetal forces on the satellite. Explain.
- Rearrange this equation to make r the subject.
- Find r. Find the height of the satellite above the equation. Mass of Earth is 5.97x10
^{24}kg. - How many times is this distance bigger than the 6380 km radius of the Earth.
- What is the name of this type of satellite?

### Past Exam Questions

In this video, I shall go through some questions from a past exam paper.

Thanks for attending this session.

Dr Hock

4 May 2014