Anything which changes or tends to change the state of rest of a body or its motion in a straight line. It can be a push, tug, squeeze, press, bend, twists or pull.
Force
Effects can cause a change in the size, shape or motion of a body
Unit of force
Newton (N)
The main unit of force(newton), is named after SirIsaacNewton
How forces can be represented
By an arrowhead - the size or magnitude of the force is represented by the length of the arrow and the direction is given by the arrow
Force representation
5 N (let 1cm = 1N)
-5 N (let 1cm = 1 N)
Resultant of two or more forces
Can be determined using a scale drawing or calculated using a number line
Weight
The force acting on an object due to gravity
Weight is dependent on the "gravity" acting on a body and as such will vary from planet to planet
Gravity enables all physical bodies to be attracted to each other
Unit of weight
Newton (N)
We could not live on Earth without gravitational forces
The sun's gravity keeps Earth in orbit around it, keeping us at a comfortable distance to enjoy the sun's light and warmth
Gravity holds down our atmosphere and the air we need to breathe
