Question

________is a force, which always opposes the motion of one body over the other body in contact with it

Answer 1

Frictional force

1. Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other.
2. The frictional force is directly proportional to the roughness of the surface. The frictional force will be more for a rough surface and it will be less for smooth surfaces.
3. Intermolecular interactions between the bodies create frictional forces.

The frictional force is a force, which always opposes the motion of one body over the other body in contact with it.