A contact force between two objects that are touching; it usually acts to slow things down or to prevent movement
Air resistance
A contact force on objects moving through the air (usually slowing the object down)
Water resistance
A contact force on objects moving through water (usually slowing the object down)
Upthrust
A contact force that pushes things upwards in liquids and gases
Gravity
A non-contact force that is a force of attraction between any two objects
Static
A non-contact force that can attract or repel things (when certain materials rub together)
Magnetism
A non-contact force that attracts objects made of iron and other magnetic materials
Weight
The force of gravity pulling on the mass of an object (measured in Newtons)
Mass
The amount of matter in an object (measured in kilograms)
Stretching
Making a material longer
Compressing
Making a material shorter
Elastic
A material that changes shape when a force is applied, but which returns to its original shape when the force is removed
Elastic limit
The point beyond which an object no longer behaves like an elastic one
Hooke's Law
The extension of a spring is proportional to the force applied (up until the elastic limit is reached)
Plastic
A material that changes shape when a force is applied, but which does not return to its original shape when the force is removed
Force meter (Newtonmeter)
A device used for measuring the size of a force
Pressure
The amount of force pushing on a certain area measure in Pascals (basically how spread out a force is)
Pressure equation
Pressure(Pa) = Force(N) / Area(m2)
SI units
Standard units used all over the World (eg time is always measured in seconds, energy is always measured in joules, pressure is always measured in pascals, force is always measured in newtons)
Balanced forces
When two forces on an object are the same strength but in opposite directions
Unbalanced forces
When two forces working in opposite directions on an object are not the same strength, resulting in a change in motion of the object