Introduction

A force has two tendencies:

• to cause translation of a body in a direction of application of the force.
• to cause rotation of the body about any point or axis, except an axis that intersects the line of action of the force or an axis that is parallel to the line of action of a force.

This tendency of a force to cause rotation is called "moment" of the force. Moment is a vector quantity denoted by $ \vec{M} $ and it is defined by the cross product, or vector product. Moment is also referred to as torque.

Some Eqs

Moment can be written in a few different ways. Here are the equations:

What these mean is if we take the distance between an origin and a torque axis and take the cross product between the two, then we can get our moment vector $ \vec{M_o} $. If we only need magnitude for the moment, then we can take the magnitude of the distance times the magnitude of the force and then multiply by the sin of the angle between the two vectors. This may be an odd concept at first, but there will be plenty of practice opportunities!