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Gravity

Revision as of 17:07, 1 November 2018 by NRJC (talk | contribs) (Key Stage 3)

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.
Gravity.png
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.
Gravity is what keeps the Earth orbiting the Sun.
Orbit1.gif
The planets are pulled towards 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.
ForcesEqual.png
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

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.