# Speed

How far something travels each second. Speed = distance / time.

Physics (school) · Part 01: Motion and measurement · Card 3 of 8 · Last updated 2026-10-19

## Analogy

Like counting how many steps you take every second.

## Example

**Sprint sum**

distance = 150 m
time = 20 s
speed = 150 / 20
speed = 7.5 m/s

## In practice

Speed cameras measure how quickly a car covers a known distance.

## Practice

### Flashcards

- **What is the formula for speed?** Speed = distance / time.
- **Convert 36 km/h to m/s.** 36 / 3.6 = 10 m/s.

## Questions people ask

### How do you calculate average speed?

Divide the total distance by the total time taken. If a car travels 120 km in 2 hours, its average speed is 60 km/h. This is an average because the car may have gone faster on some parts of the trip and slower, or stopped, on others.

### How do you change km/h into m/s?

Divide by 3.6. A speed of 72 km/h becomes 20 m/s. This works because one kilometre is 1,000 metres and one hour is 3,600 seconds, so you divide 1,000 by 3,600. To go back the other way, multiply by 3.6.

## Related concepts

- [SI units](https://studyvisually.com/learn/science/physics-school/physics-school-part-1/physics-school-part-1-concept-1)
- [Velocity](https://studyvisually.com/learn/science/physics-school/physics-school-part-1/physics-school-part-1-concept-4)
- [Distance-time graph](https://studyvisually.com/learn/science/physics-school/physics-school-part-1/physics-school-part-1-concept-5)
- [Acceleration](https://studyvisually.com/learn/science/physics-school/physics-school-part-1/physics-school-part-1-concept-6)

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