We typically measure the mass of a body by first measuring the weight using a scale, and then calculating mass from the measured weight. Often W is used to abbreviate weight, but is also used because ...We typically measure the mass of a body by first measuring the weight using a scale, and then calculating mass from the measured weight. Often W is used to abbreviate weight, but is also used because it reminds us that an object’s weight and the force of gravity on the object are the same thing. We usually try to make the length of the arrows proportional to how big the forces are, in which case the arrows can be called vectors.
