Contents
Key Stage 2
Meaning
Gravity is a force that causes all objects to be attracted to each other.
About Gravity
- Gravity is a non-contact force.
- Gravity affects all objects.
- Gravity pulls us down towards the centre of the Earth.
If person A drops the cog it will fall towards the centre of the Earth. If person B drops the spanner it will fall towards the centre of the Earth. |
The planets are pulled towards the The Sun by gravity. |
Key Stage 3
Meaning
Gravity is a force that causes all objects with mass to be attracted to each other.
About Gravity
- Gravity is a force so it is measured in Newtons.
- Gravity is a non-contact force because it can act without objects touching.
- All objects are affected by gravity.
- Gravity is the force that pulls objects to the ground.
- Isaac Newton was the first to realise that gravity is the force that holds the planets in orbit around The Sun.
- The force of gravity between two objects is always equal in magnitude but opposite in direction.
Object A has 1kg of mass and is attracted to object B. Object B has 2kg of mass and is attracted to object A. The force acting on object A is the same as the force on object B. |
Falling
Energy Transfers
Accelerating
- When an object accelerates towards the ground energy is transferred from the gravitational potential energy store of the object to the kinetic energy store of the object.
Decelerating
- When an object decelerates away from the ground energy is transferred from the kinetic energy store of the object to the gravitational potential energy store of the object.
Forces
Accelerating
- When an object accelerates towards the ground gravity is causing a mechanical energy transfer.
Decelerating
- When an object decelerates away from the ground gravity is causing a mechanical energy transfer.
Orbits
- Newton was the first person to realise that objects were held in orbit by gravity which he explained in his Universal Theory of Gravitation.
- Moons orbit planets and planets orbit the stars due to gravity.
- Gravity is a constant force directed to the centre of a massive object.
- The Moon feels a force pulling it towards the centre of the Earth. The Earth feels a force equal in magnitude but opposite in direction to that of The Moon.
The planets are pulled towards The Sun by gravity. |