The right hand screw rule can be used when a direction must
determined based upon a rotational direction, or vice versa. It is best
illustrated using a diagram.
axis is 'grasped' in the right hand, the fingers curl
round in the
direction of positive rotation and the thumb is orientated in the
positive direction. Therefore if the direction of rotation is know the
fingers can be curled in this orientation and the thumb will point in
the positive direction, and vice versa.