A flat plate is placed within the plane of the paper. The plate is rotating counterclockwise around an axis that is perpendicular to the plate. The direction of its angular momentum is
A) out of the paper toward the observer.
B) into the paper away from the observer.
C) counterclockwise in the plane of the paper.
D) clockwise in the plane of the paper.

Question

Quizplus · Accepted Answer

The direction of angular momentum is determined by the right-hand rule, which states that if you curl the fingers of your right hand in the direction of rotation, your thumb points in the direction of the angular momentum. Since the plate is rotating counterclockwise, when applying the right-hand rule, your thumb points out of the paper toward the observer.

A Flat Plate Is Placed Within the Plane of the Paper