What is a force?
A force can change the shape speed or direction of an object.
What is weight?
The force which pulls all objects down to the centre of the planet.
What is friction?
A force which acts between two surfaces and tries to stop objects moving.
What is magnetic force?
Force created by magnetic materials.
What is electrostatic force?
Force created by rubbed plastic objects like balloons.
What is upthrust?
The force pushing up on something which is placed in water.
What is tension?
Force which acts through stretched ropes elastic bands and springs.
What is reaction force?
The force pushing up on you when you stand on the ground or sit on a chair.
What is the unit of force?
Newton.
What are the units for force written as?
Newtons or N.
What are balanced forces?
Forces with same size but opposite directions.
What do balanced forces do?
They cancel each other out.
What happens if balanced forces act on an object?
Its motion does not change.
What is mass?
A measure of how much matter is in an object.
Does mass change anywhere in the universe?
No it stays the same.
What causes weight?
A vertical force field called gravity.
What is gravitational field strength on Earth?
10 N/kg.
How do you calculate weight?
Weight = mass × g.
What is the weight of a 60 kg person on Earth?
600 N.
What is the weight of a 60 kg person on Mars if gravity is 4 N/kg on Mars?
240 N.
What is air pressure?
The force made when fast-moving air particles hit a surface.
What causes air pressure?
Particles hitting a surface.
What is friction?
A force which acts between moving surfaces.
What is the transfer of energy when friction acts?
Movement energy turns to heat.
