Question

The ___________ forces do not cause the rotation if the rotation is considered in about the axis of the body or the centroid axis of the body.

(a) Non-concurrent

(b) Concurrent

(c) Parallel

(d) Non-Parallel

I had been asked this question in an internship interview.

I'd like to ask this question from Moment of a Force on a Specified Axis topic in portion Force System Resultants of Engineering Mechanics

Answer 1

Correct answer is (b) Concurrent

To explain: The concurrent forces are the which are somewhere touching the axis of rotation. If any of the force is touching that axis, that force is not considered or is insufficient to cause a rotation. If a force is concurrent then the perpendicular distance of the force from the line of an axis is zero, thus no rotation. As we know rotation is caused by a moment.