(a) Friction opposes the motion between the surfaces in contact with each other.
(b) Friction depends on the nature of surfaces.
(c) Friction produces heat.
(d) Sprinkling of powder on the carrom board reduces friction.
(e) Sliding friction is lesser than the static friction
Friction opposes the motion between the surfaces in contact with each other because it creates interlocking between the two surfaces in contact in such a way that the relative motion of the object slows down and direction of frictional force is shown in the opposite direction to the motion of the object.
Friction depends on the nature of surfaces because friction is all about interlocking which arises because of the roughness of a surface. If the surface is more rough then it undergoes more interlocking with the other surface in contact, thus resulting in more friction. And if the surface is smooth or less rough then it undergoes less interlocking with the other surface in contact, thus resulting in less friction.
Friction produces heat when an object forcibly tries to overcome the interlocking between its own surface and the surface that is in contact with it.
Sprinkling of powder on the carrom board reduces friction because the powder fills the roughness on the surface of the carrom board thus reducing interlocking and making it easy for the dots and striker to move on the board.
Sliding friction is lesser than the static friction because sliding motion allows less time for interlocking, thus making the interlocking less strong, while static motion allows more time for interlocking, thus resulting in a stronger interlocking and providing more friction than the sliding one.