Mass vs weight
Mass is matter (kg); weight is gravity's force on it (N).
The common mistake
Giving weight in kilograms, or saying mass changes on the Moon.
Instead: W = m × g. Mass stays the same everywhere; weight depends on g (9.8 N/kg on Earth, about 1.6 on the Moon).
Worked example with Guide me
What does a 60 kg person weigh on Earth (g = 9.8 N/kg)?
- Sugar · Which formula?Student · W = mg.
- Sugar · Multiply.Student · 60 × 9.8 = 588.
Answer: 588 N
Try 3 practice questions
1. Mass of that person on the Moon?
Show answer
Still 60 kg
2. Weight of 2 kg on Earth (g = 10)?
Show answer
20 N
3. Mass of something weighing 49 N (g = 9.8)?
Show answer
5 kg
Quick answers
- What is the most common mistake with mass vs weight?
- Giving weight in kilograms, or saying mass changes on the Moon.
- How do I get mass vs weight right?
- W = m × g. Mass stays the same everywhere; weight depends on g (9.8 N/kg on Earth, about 1.6 on the Moon).
- Can you show a worked example?
- What does a 60 kg person weigh on Earth (g = 9.8 N/kg)? 588 N
Related concepts
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