[Leejohnston]

## Distance = Speed × Time — The Most Useful Equation You Ever Learned

### 1. The Equation

Distance = Speed × Time

Often written as:
d = v × t

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### 2. What Each Symbol Means

- d = distance
- v = speed (velocity)
- t = time

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### 3. What the Equation Is Telling Us

This equation links **motion and time**.

If you know any two quantities, you can always find the third.

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

Speed literally means:
“How much distance is covered per unit time”

Multiply that rate by time → total distance travelled.

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### 5. Worked Example

**If a car travels at 60 mph for 2.5 hours:**

Distance = 60 × 2.5
= **150 miles**

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### 6. Real-World Applications

- Journey planning
- Fuel estimates
- Space travel calculations
- Sports performance analysis

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### 7. Common Mistakes

- Mixing units (mph with seconds)
- Forgetting to convert time
- Assuming speed is constant when it isn’t

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### Try It Yourself

If light travels at 300,000 km/s:
- How far does it go in 1 second?
- How far in 1 minute?