Mass versus weight

The chains on the swing hold all the child’s weight. If one were to stand behind her at the bottom of the swing and try to stop her, they would be acting against her inertia, which comes from mass, not weight.

In the physical sciences, mass and weight are different. Mass is a measure of the amount of matter in the body while weight is a measure of the force on the object caused by a gravitational field.

This means the mass of an object will remain at wherever it is on the earth’s surface, but if it is moved from the equator to the North Pole, its weight will grow by 0.5% because of the increase in the earth’s gravitational field.

Overview

Mass to the general means of how “heavy” something is. However, mass is really an inertial property; that is, the tendency of an object to remain at constant velocity unless acted upon by an outside force. According to Newton's second law of motion, as expressed in the formula an object with a mass, m, of one kilogram will accelerate, a, at one meter per second per second (about one-tenth the acceleration due to earth’s gravity) when acted upon by a force, F, of one newton.

Related pages

• Mass
• Force
• Weight