Chapter 16/17 - Circular Motion + Gravitational Fields

Angular displacement

The angle of arc through which the object has moved from its starting position.

Radiants

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

Centripetal force

The resultant force acting on an object toward the center of the circle when the object is rotating round that circle at constant speed.

Centripetal acceleration

The acceleration of an object towards the center of the circle when the object is rotating at constant speed round that circle.

Newton’s law of gravitation

states that the gravitational force is directly proportional to the product of masses and inversely proportional to the square of their separation

gravitational field

tells us about the force on unit mass at a point 

gravitational potential

it is the work done to bring a unit mass from infinity to that point (note that it is negative and increases with distance therefore becomes less negative or closer to infinity=0)

orbital period 

the time taken by an object (such as a planet) to complete one orbit 

geostationary orbit 

an orbit of a satellite such that the satellite remains directly above the same point of the Earth at all times