Module 5: Gravitational fields

Why do gravitational fields exist?

Due to objects having mass

When can gravitational field be assumed to be uniform?

Closer to the surface of the Earth

What are Kepler’s Laws?

1. The orbit of a planet is an ellipse with the sun at one of the foci

2. A line segment joining the sun and a planet sweeps out equal areas in equal times

3. The square of the orbital period of a planet is proportional to the cube of its orbital distance

What 3 things are true about geostationary satellites?

1. They have an orbital period of 24 hours

2. They are an equatorial orbit

3. They remain fixed in the sky to an observer on Earth

What is the definition of gravitational potential energy?

Work done to bring a unit mass from infinity to the point