Contact Forces
Forces that exist between objects that are touching, or in contact, are known as contact forces. Five contact forces are:
Normal Reaction Force
This force opposes gravity, preventing objects from falling through each other.
Upthrust
This is an upward force that supports an object within a fluid (liquid or gas), causing it to float.
Air Resistance
This force occurs when air particles oppose the direction of a moving object to slow it down.
Thrust
This is a force that propels an object in one direction.
Friction
This force occurs between two surfaces that causes moving objects to slow down or stop.