Mass and Weight

Key Concepts

Mass

Amount of matter an object contains; measure of its inertia.

Weight

Gravitational force acting on a mass or object.

Weight Calculation

On Earth's surface (g ≈ 9.80 m/s²):

W = mg

Where: W = Weight, m = Mass, g = Acceleration due to gravity

Measuring Force and Mass

Spring Scale

Uses a spring that stretches when force is applied. Measures force with a graduated scale.

Force Sensor

Electronic gauge for high-accuracy force measurement. Provides digital readout or graph.

Mass from Weight

Converting weight to mass:

m = W / g

Where: m = Mass, W = Weight, g = Acceleration due to gravity

Example: Weight on Earth vs Moon

Given: Mass of school bag = 8 kg

Earth's g = 9.8 m/s², Moon's g = 1.625 m/s²

Weight on Earth:

W₁ = 8 kg × 9.8 m/s² = 78.4 N

Weight on Moon:

W₂ = 8 kg × 1.625 m/s² = 13 N