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...
Angular Speed Any object travelling in a uniform circular motion at the same speed travels with a constantly changing velocity This is because it is constantly changing direction, and is therefore ...
Radians & Angular Displacement In circular motion, it is more convenient to measure angular displacement in units of radians rather than units of degrees The angular displacement (θ) of a body ...
Quark Composition: Protons & Neutrons Protons and neutrons are not fundamental particles. They are each made up of three quarks Protons are made up of two up quarks and a down quark Neutrons ar...
