Planets and forces

Planets and forces

1. Radian: the angle subtended at the centre of a circle by an arc of length equal to the radius of the circle.

2. Centrepetal force: net force moving on an object in a circle.

3. Newton's law of gravitation: any two point masses attract each other with a force directly proportional to the product of their masses and inversley proportional the the square of their seperation.

4. Gravitational feild strength: the gravitational force exterted per unit mass of a small object placed on that point.

   • G=Fm

5. Kepler's 3rd law of planetary motion: the t squared of a planet is proportional to r cubed from the sun.

6. Feild: the region of space surrounding a body where other bodies feel a force due to it.

7. F=GMm/r2 - the force of attraction between 2 masses.

8. Geostationary satelites have a 24 hour orbit.