Question

It is easier to roll a barrel than pull it along the road. This statement is.
A. False
B. True
C. Uncertain
D. Not possible

Answer 1

Hint: In order to get the answer for the given statement first we need to know what type of frictional force will be applied on the barrel while rolling and pulling and how much amount also. When we get what type of and how much amount of frictional force is applied then we get the actual force needed to apply for the barrel to roll or pull.

Formula used:
\[{f_S} \gg {f_R}\]
Where, ${f_S}$ is sliding friction applied when the barrel is pulled and ${f_R}$ is rolling friction applied when the barrel is rolled.

Complete step by step solution:
When the barrel is pulled, then sliding friction is applied that is ${f_S}$. When the barrel is rolled, the rolling friction will be ${f_R}$. We know that the value of sliding friction is much more than the rolling friction.
\[{f_S} \gg {f_R}\]
Now, we know that friction is the force that resists the motion of the body in contact with each other. Here it is a barrel that is in contact with the surface of the road. So, both the sliding friction and rolling friction which oppose the motion of the barrel on the road.

To balance this resistance force we apply the same amount of force in the opposite direction of frictional force. Let the force applied while pulling/sliding be ${F_S}$. And the force applied while rolling be ${F_R}$. Now, to balance the force sliding friction should be equal to sliding force.
${f_S} = {F_S}$
Also rolling friction should be equal to rolling force.
${f_R} = {F_R}$
As, \[{f_S} \gg {f_R}\]
So, ${F_S} \gg {F_R}$ must be true.
Therefore, it is easy to roll a barrel then to pull it along the road.

Hence, the correct answer is option B.

Note: Here we needed to compare the two types of frictional force that is sliding friction and rolling friction. Also we know that sliding friction is much greater than rolling friction but it is not the case all the time. Surface and the inclination of the body on the surface also matters in the same cases.