# Metric Speed (Velocity)

These are the most common measurements:

**Meters per second (m/s)****Kilometers per hour (km/h)**

### Speed in meters per second (m/s)

If something is traveling at 1 m/s it moves **1 meter every second**.

It is a gentle walking speed.

One hour walking at 1 m/s moves you 3.6 km.

### Speed in kilometers per hour (km/h)

If something is traveling at 1 km/h it moves **1 kilometer every hour**.

1 km/h is like a **very slow** walking speed.

Kilometers per hour is often used for car speeds.

### Example: Highway speed is around **100 km/h**

One hour at this speed moves you 100 km.

### Example: One **minute** at 60 km/h moves you **1 km**.

## Converting

You can convert from m/s to km/h:

- 1 m/s = 3.6 km/h
- 1 km/h = 0.2777... m/s

### Example: What is 100 km/h in m/s?

A kilometer has 1,000 meters, and an hour has 3,600 seconds, so 100 kilometers per hour is:

- 100 x 1,000 / 3,600 = 27.777... m/s

100 km/h = 27.78 m/s (to 2 decimal places)

## Velocity

Velocity is speed with a **direction**.

So if something is moving at 5 km/h that is a speed.

But when we say it is moving at **5 km/h westwards** that is a **velocity**.

If something moves backwards and forwards very fast it has a high speed, but a low (or zero) velocity

## Examples

100 km/h is about:

- how fast we can legally go on many highways
- the maximum running speed of a cheetah
- half the freefall speed of a skydiver

60 km/h is about:

- going very fast on a bicycle
- the speed needed to go one kilometer in a minute
- the speed of a racehorse on a short track
- full running speed of a Bengal Tiger

1 meter per second is:

- about 3.2808 feet per second

1 kilometer per hour is

- about 0.9113 feet per second