Weight of an Object on Earth and Moon
What Is Weight?
Weight is the force with which a planet attracts an object toward its center.
It depends on:
- Mass of the object
- Gravitational acceleration of the planet
Formula:
Weight (W) = Mass (m) × Gravitational acceleration (g)
Weight on Earth
- Gravitational acceleration on Earth (gₑ) ≈ 9.8 m/s²
- Earth has stronger gravity, so objects weigh more here.
Weight on Moon
- Gravitational acceleration on Moon (gₘ) ≈ 1.62 m/s²
- Moon’s gravity is weaker, so objects weigh less.
The Moon’s gravity is about 1/6th of Earth’s gravity.
Comparison Table: Weight on Earth vs Moon
| Property | On Earth | On Moon |
|---|---|---|
| Gravitational acceleration (g) | 9.8 m/s² | 1.62 m/s² |
| Weight of object | More | Less |
| Effect of gravity | Strong | Weak |
| Change in mass | No change | No change |
Example Calculation
Suppose an object has a mass of 60 kg
Weight on Earth:
Wₑ = 60 × 9.8 = 588 N
Weight on Moon:
Wₘ = 60 × 1.62 = 97.2 N
The object weighs much less on the Moon, but its mass remains the same.
Important Points for Exams
- Mass is constant everywhere
- Weight changes from place to place
- Weight on Moon = 1/6 × Weight on Earth
- Astronauts appear to “jump higher” on the Moon due to lower gravity
One-Line Answer (Exam Ready)
The weight of an object on the Moon is one-sixth of its weight on Earth because the Moon’s gravitational acceleration is much smaller.