Adhesive forces

Q. How the use of oil reduces friction between two surfaces in contact with each other.

Q. Why is there a high friction between two smooth glass pieces?

1. It is due to bond formation between the surfaces.
2. It is due to interlocking between the surfaces.
3. It is due to deformation of the surfaces.
4. It is due to irregularities present on the surfaces.

Q. Considering no air drag, if a ball starts moving on a frictionless horizontal surface, it will:

1. never stops
2. stops after short duration
3. cannot be determined
4. stops after long duration

Q.

How is friction between coins and carrom board affected when some powder is sprinkled on the carrom board?

1. It increases a little.

2. It increases to a large extent.

3. It doesn't change.

4. It decreases.