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Types of Friction
Friction is a force that resists the motion of objects that are in contact with one another. Friction basically opposes the motion of an object. Think about if you gave a book a push across your desk. The book would eventually come to a stop.
What force acted on the book to cause it to stop? Friction. There was friction between the book and the surface of the desk, which eventually caused the book to stop sliding.
Types of Friction
There are several types of friction:
- Static friction (occurs when objects are not moving)
- Kinetic friction (occurs when objects are moving)
- Sliding friction
- Rolling friction
Static friction acts on objects that are not moving. It is the strongest type of friction. Imagine pushing your dresser across the room. Initially, it is difficult to get the dresser to move. This is because of static friction.
Once the dresser you're pushing begins to move or slide across the floor, it is much easier to move. This is due to sliding friction. Sliding friction acts on objects that are sliding past each other. Sliding friction is a type of kinetic friction.
Another type of kinetic friction is rolling friction. It acts on objects that are rolling past each other. It is the weakest type of friction. It makes setting objects with wheels into motion easy. Imagine how simple it is to push a toy car across the floor.