[Leejohnston]

## Gravity — Why Everything Falls the Same Way

### 1. The Equation

Force of gravity:
F = G × (m₁m₂) ÷ r²

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### 2. What Each Symbol Means

- F = gravitational force
- G = gravitational constant
- m₁, m₂ = masses
- r = distance between centres

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### 3. What the Equation Is Telling Us

Gravity depends on:
- how massive objects are
- how far apart they are

Distance matters a lot — it’s squared.

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### 4. Where It Comes From (Intuition)

Gravity spreads out in space.

As distance increases, the same influence is spread over a larger area, so it weakens rapidly.

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### 5. Worked Example

If distance doubles:
- gravity becomes **four times weaker**

This is why gravity drops off quickly with height.

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### 6. Real-World Applications

- Planetary orbits
- Satellite motion
- Tides
- Astrophysics

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### 7. Common Misconceptions

- Heavier objects fall faster → false
- Gravity only exists near Earth → false
- Gravity is a force pulling downward → incomplete

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### Try It Yourself

What happens to gravity if:
- distance triples?
- mass doubles?