Contact Forces
- A contact force is defined as:
A force which acts between objects that are physically touching
- Examples of contact forces include:
- Friction
- Air resistance
- Tension
- Normal (reaction) force
Friction
- Friction is a force that opposes motion
- Occurs when objects rub against each other e.g. car wheels on the ground
Air resistance
- Air resistance is a type of friction
- Occurs when an object moves through air e.g. an object in freefall
Tension
- Tension is a force that pulls two objects connected by a length of something, such as a string or rope
- Occurs when a force is applied to the length e.g. a spring extending
Normal / reaction force
- Reaction forces occur when an object is supported by a surface
- It is the component of the contact force acting perpendicular to the surface that counteracts the body e.g. a book on a table
Examples of contact forces