Answer:
Rubber on steel and Rubber on dry concrete
Explanation:
Friction is the force of resistance on the solid motion surfaces.
Coefficient of The ratio of frictional force between two body and the forces that brings them together. It depends on the temperature, velocity of the object involved.
Rubber is said to exhibit a high coefficient of friction with other surface ranging from 1 to 2 while Dry surface material yield between 0.3 to 0.6. When friction is greater than 1 it means the force that is needed to slide or move an object on the surface is greater than the force that exist on the surface of the object.
