### Circular motion and gravity

The speed of an object in circular motion is most often measured as the angular velocity. The connection between speed and angular velocity is explained in the first notes sheet.

The circling object needs a force towards the centre to keep in moving in that circle so the second notes sheet goes through the maths connecting force and speed / angular velocity.

Satellites orbits are usually nearly circular, the force (using Newtonian mechanics) being provided by gravity. The two subsequent sets of notes explain Newton's Law of Gravity and application to satellites.

The fifth sheet is on gravitational potential which is a more difficult idea contained in many advanced level school syllabuses.

The final sheet of notes explains the classic experiment to find the charge to mass ratio of electrons connecting the strength of the magnetic field to the radius of the electron path and the velocity of the particles.

There is a free video on satellites within the astronomy section here.

There is a much more detailed group of video lessons on circular motion and gravity to buy on flash drive, details are here.