# Weight

The pull of gravity on an object, found with W = mg. Mass stays the same everywhere, weight does not.

Physics (university) · Part 02: Newton's laws and forces · Card 5 of 10 · Last updated 2026-10-19

## Analogy

Your mass is how much stuff you are made of. Your weight is how hard Earth pulls it.

## Example

**Weight on Earth**

W = m g
W = 70 kg x 9.8 m/s^2
W = 686 N

## In practice

A 70 kg person weighs about 686 N on Earth and about 113 N on the Moon.

## Practice

### Flashcards

- **What is the weight of a 10 kg mass on Earth?** About 98 N.

## Questions people ask

### Why is weight different on the Moon?

Weight is mass times local gravity. The Moon's surface gravity is about 1.6 m/s^2, roughly one sixth of Earth's. A 60 kg person weighs about 588 N on Earth and only about 96 N on the Moon, but their mass is still 60 kg.

### Is weight measured in kilograms?

In physics, no. Weight is a force, so its SI unit is the newton. People say a bag weighs 5 kg in daily life, but they really mean its mass. The weight of a 5 kg bag on Earth is about 49 N.

## Related concepts

- [Newton's first law](https://studyvisually.com/learn/science/physics-university/physics-university-part-2/physics-university-part-2-concept-1)
- [Net force](https://studyvisually.com/learn/science/physics-university/physics-university-part-2/physics-university-part-2-concept-2)
- [Newton's second law](https://studyvisually.com/learn/science/physics-university/physics-university-part-2/physics-university-part-2-concept-3)
- [Newton's third law](https://studyvisually.com/learn/science/physics-university/physics-university-part-2/physics-university-part-2-concept-4)

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