[Leejohnston]

## Torque — Why Levers Multiply Force

### 1. The Equation

Torque = Force × Distance

τ = F × r

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### 2. What Each Symbol Means

- τ = torque
- F = applied force
- r = distance from pivot

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### 3. What the Equation Is Telling Us

Force applied farther from a pivot produces **more rotational effect**.

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

A longer lever arm gives force more leverage.

That’s why long wrenches loosen tight bolts.

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### 5. Worked Example

If:
- Force = 50 N
- Distance = 0.4 m

Torque = 20 N·m

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### 6. Real-World Applications

- Door handles
- Seesaws
- Engine crankshafts
- Human joints

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### 7. Common Misconceptions

- Bigger force always wins → false
- Torque equals force → false
- Rotation needs constant force → false

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### Try It Yourself

Why are door handles placed far from hinges?