When two bodies are kept in contact, electromagnetic forces act between the charged particles (molecules)
at the surfaces of the bodies
(i) nter-locking of extended parts of one object into the extended parts
of the other object.
Kinetic Friction Force
Kinetic friction exists between two contact surfaces only when there is relative motion between
the two contact surfaces. It stops acting when relative motion between two surfaces ceases.
?t exists between the two surfaces when there is tendency of relative motion but no
relative motion along the two contact surface
Kinetic friction :
The magnitude of the kinetic friction is proportional to the normal force acting between the two bodies.