Question
What is friction and what is the cause of friction?
Solution
When a body actually moves or tends to move over the surface of another body, frictional force comes into play as the retarding force.
The surface of a moving body is not perfectly smooth. even though it appears to be smooth, there are irregularities on the surface.
When a body is placed on the second body, the irregularities of the two surfaces get interlocked. To break the interlocking, we have to apply the force. Therefore, the cause of friction is interlocking of irregularities.
