6. It is easier to roll a barrel full of coal tar than to pull it because A.the full weight of the barrel comes into play when it is pulled B.the rolling friction is much less than the sliding friction C.more surface area of the barrel is in contact with the road when it is pulled D.coal tar is a liquid and it flows in the barrel when it is rolled
Option B Solution: When a body slides (moves with all its surface area in contact) over another body, the resistance faced is due to sliding friction. Hence rolling friction is less than the sliding friction. Thus it is easier to roll a barrel full of coal tar than to pull it.
