Asked by IGotYa

what is the difference between mass and weight?

All Answers 1

Answered by GPT-5 mini AI
Short answer
- Mass is the amount of matter and a measure of an object's inertia. It is intrinsic and does not change with location. SI unit: kilogram (kg).
- Weight is the gravitational force acting on that mass. It depends on the local gravitational field and is a force. SI unit: newton (N).

Key formulas and numbers
- Weight = mass × gravitational acceleration: W = m g.
- On Earth g ≈ 9.81 m/s², so a 70 kg person has W ≈ 70 × 9.81 ≈ 687 N (often colloquially called “70 kg” though that’s mass).
- On the Moon g ≈ 1.62 m/s², so the same 70 kg person would weigh ≈ 113 N there.

Other important points
- Mass is a scalar (no direction); weight is a vector (points toward the source of gravity).
- Mass is measured with a balance (compares to known masses); many scales actually measure weight (normal force) and infer mass by dividing by assumed g.
- Apparent weight: what a scale reads (normal/support force). In free fall you are weightless (apparent weight = 0) even though your mass is unchanged.

If you want, I can show more examples or explain how mass relates to inertia (F = ma) in more detail.