Which of the following statements is correct?
I. Rolling friction is greater than the sliding friction.
II. The frictional force exerted by fluids is called drag.
Answer & explanation
Correct answer: option 4
The correct answer is option 4. Only II is correct.
I. Rolling friction is greater than sliding friction is incorrect. In fact, rolling friction is typically less than sliding friction. When an object rolls, only a small portion of its surface comes into contact with the surface it's rolling on, resulting in less friction compared to sliding, where the entire surface is in contact.
II. The frictional force exerted by fluids is called drag is correct. Drag force is the force exerted by a fluid (liquid or gas) on an object moving through it, and it opposes the motion of the object.