Question

introduction of friction

Answer 1

friction is the force experienced by two surfaces in contact due to interlocking of rough edges

Answer 2

friction, force that resists the sliding or rolling of one solid object over another. Frictional forces, such as the traction needed to walk without slipping, may be beneficial; but they also present a great measure of opposition to motion. About 20 percent of the engine power of automobiles is consumed in overcoming frictional forces in the moving parts.