Question

In the equation Wa/r generally used in the rolling frictional calculations, what does each stands for?

(a) P is the force, W is weight of the body, r radius and a coefficient of rolling friction all in normal powers

(b) P is the force in nano Newton, W is weight of the body, r radius and a coefficient of rolling friction

(c) P is the force, W is weight of the body in kg, r radius and a coefficient of rolling friction

(d) P is the force, W is weight of the body, r radius cm and a coefficient of rolling friction

This question was addressed to me at a job interview.

Origin of the question is Rolling Resistance in division Friction of Engineering Mechanics

Answer 1

The correct option is (a) P is the force, W is weight of the body, r radius and a coefficient of rolling friction all in normal powers

To explain: The rolling of the cylinder is termed as perfect rolling only when the cylinder is rolling at a constant velocity. Also, the rolling should be along the rigid surface. The normal forces are acting perpendicular to the surface of the rolling. And for rolling equation, Wa/r is generally used.