Question

What are the sign conventions for anticlockwise and clockwise rotations of moment?

Answer 1

As a matter of convention, an anticlockwise moment is taken as positive and a clockwise moment is taken as negative. The direction of a moment depends upon the axis of rotation with respect to which you are measuring the turning effect. Clockwise and counterclockwise qualifications are dependent upon the observer's viewpoint. For example, if you place a book on a table and take an axis through the book's centre vertically, a force applied rightwards to the top edge would be considered clockwise while a force applied rightwards to the bottom edge would be considered anticlockwise if you are seeing from above.