3.1.6—The concept of weight as the effect of a gravitational field on a mass and

Weight W=mg is the force exerted by a gravitational field on mass m. Its direction is toward the field source and its value depends on local g.

Use mass in inertial equations and weight as a force in free-body diagrams. In a non-uniform field, g can vary with position.

A 5 kg mass near Earth has weight about 49 N downward when g=9.8 m s⁻².

Weight is not mass, and apparent weight measured by a scale can differ from mg during acceleration.