The Value of g on Earth Gravitational field strength g is approximately constant for small changes in height near the Earth’s surface (9.81 m s-2) This is because from the inverse square law relati...
Deriving Gravitational Field Strength (g) The gravitational field strength at a point describes how strong or weak a gravitational field is at that point The gravitational field strength due to a p...
Geostationary Orbits Many communication satellites around Earth follow a geostationary orbit This is a specific type of orbit in which the satellite: Remains directly above the equator, therefore, ...
Circular Orbits in Gravitational Fields Since most planets and satellites have a near circular orbit, the gravitational force FG between the sun or another planet provides the centripetal force nee...
Newton's Law of Gravitation The gravitational force between two bodies outside a uniform field, e.g. between the Earth and the Sun, is defined by Newton’s Law of Gravitation Recall that the mass of...
Defining Gravitational Field There is a force of attraction between all masses This force is known as the ‘force due to gravity’ or the weight The Earth’s gravitational field is responsible for the...
Calculating Centripetal Force An object moving in a circle is not in equilibrium, it has a resultant force acting upon it This is known as the centripetal force and is what keeps the object moving ...
Calculating Centripetal Acceleration Centripetal acceleration is defined as: The acceleration of an object towards the centre of a circle when an object is in motion (rotating) around a circle at a...
What Causes Centripetal Acceleration? Velocity and acceleration are both vector quantities An object in uniform circular motion is continuously changing direction, and therefore is constantly cha...
