It is easier to roll a wooden cylindrical barrel instead of pulling it, because

It is easier to roll a wooden cylindrical barrel instead of pulling it because the friction force of rolling state is much less than the friction force of sliding state (B). When the barrel rolls, only a small portion of its surface area is in contact with the ground at any given time, reducing friction. In contrast, when pulled, the entire bottom surface of the barrel is in contact with the ground, resulting in higher friction. Option (A) is incorrect because the weight of the object is effective regardless of whether it’s rolled or pulled. Option (C) is also incorrect because the surface area of the barrel in contact with the road doesn’t affect the friction force. Therefore, the correct option is (B) The friction force of rolling state is much less than the friction force of sliding state.