Question

If you are getting to know about the direction of the moment caused by the force applied on the body by using your wrist and curling it in the direction of the rotation then which of the following is not right?

(a) The thumb represents the direction of the force

(b) The thumb represents the direction of the moment

(c) The fingers represent the direction of the force

(d) The direction in which you curl your wrist is towards the direction of the distance from point of contact of force to the axis of rotation.

The question was asked in a national level competition.

My question is from Moment of a Force topic in portion Force System Resultants of Engineering Mechanics

Answer 1

Correct answer is (b) The thumb represents the direction of the moment

For explanation I would say: The curled hand represents a various thing. The direction of the moment axis is given by the thumb. The direction of the force is given by the fingers. As we place the fingers on the force and curl towards the rotational direction of the body about the axis.