Weight, Mass & Gravity Flashcards

All 6 cards in this deck

Define weight.

The force acting on an object due to gravity (due to the gravitational field it is in), measured in newtons.

State the equation linking weight, mass and gravitational field strength, with units.

weight (N) = mass (kg) × gravitational field strength (N/kg), i.e. $W = m \times g$

How is the weight of an object measured?

By hanging it from a calibrated newtonmeter (spring balance / force meter) and reading the force in newtons.

Describe the relationship between the weight of a body and the gravitational field strength at its location.

Weight is directly proportional to gravitational field strength — for a fixed mass, doubling $g$ doubles the weight.

What are the steps to find the mass of an object from its weight?

e.g. weight $50$ N where $g = 10$ N/kg

1. Rearrange $W = m \times g$ to $m = W \div g$
2. Substitute: $m = 50 \div 10$
3. Mass $= 5$ kg

True or false? An astronaut's mass is smaller on the Moon than on Earth.

False. Mass is the same everywhere; only the weight is less because the Moon's gravitational field strength is smaller.