# 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

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

• 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