 x Metre per second Encyclopedia
Metre per second is an SI derived unit
SI derived unit
The International System of Units specifies a set of seven base units from which all other units of measurement are formed, by products of the powers of base units. These other units are called SI derived units, for example, the SI derived unit of area is square metre , and of density is...

of both speed
Speed
In kinematics, the speed of an object is the magnitude of its velocity ; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance traveled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as...

(scalar
Scalar (physics)
In physics, a scalar is a simple physical quantity that is not changed by coordinate system rotations or translations , or by Lorentz transformations or space-time translations . This is in contrast to a vector...

) and velocity
Velocity
In physics, velocity is speed in a given direction. Speed describes only how fast an object is moving, whereas velocity gives both the speed and direction of the object's motion. To have a constant velocity, an object must have a constant speed and motion in a constant direction. Constant ...

(vector quantity which specifies both magnitude and a specific direction), defined by distance
Distance
Distance is a numerical description of how far apart objects are. In physics or everyday discussion, distance may refer to a physical length, or an estimation based on other criteria . In mathematics, a distance function or metric is a generalization of the concept of physical distance...

in metre
Metre
The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...

s divided by time
Time
Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....

in second
Second
The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....

s.

The official SI
Si
Si, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system...

symbolic abbreviation
Abbreviation
An abbreviation is a shortened form of a word or phrase. Usually, but not always, it consists of a letter or group of letters taken from the word or phrase...

is m·s−1, or equivalently either m/s or . Where metres per second are several orders of magnitude too slow to be convenient, such as in astronomical
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

measurements, velocities may be given in kilometres per second, where 1 km/s is 1000 metres per second.

## Conversions

1 m/s is equivalent to:
= 3.6 km·h−1 (exactly)
≈ 3.2808 feet per second
Feet per second
The foot per second is a unit of both speed and velocity . It expresses the distance in feet traveled or displaced, divided by the time in seconds...

(approximately)
≈ 2.2369 miles per hour
Miles per hour
Miles per hour is an imperial unit of speed expressing the number of statute miles covered in one hour. It is currently the standard unit used for speed limits, and to express speeds generally, on roads in the United Kingdom and the United States. It is also often used to express the speed of...

(approximately)
≈ 1.9438 knots (approximately)

foot per second
Feet per second
The foot per second is a unit of both speed and velocity . It expresses the distance in feet traveled or displaced, divided by the time in seconds...

= 0.3048 m·s−1 (exactly)

1 mile per hour = 0.44704 m·s−1 (exactly)

1 km·h-1 ≈ 0.2778 m·s−1 (approximately)

1 kilometre per second is equivalent to:
≈ 0.6213 miles per second (approximately)
≈ 2237 miles per hour
Miles per hour
Miles per hour is an imperial unit of speed expressing the number of statute miles covered in one hour. It is currently the standard unit used for speed limits, and to express speeds generally, on roads in the United Kingdom and the United States. It is also often used to express the speed of...

(approximate)

## Relation to other measures

Although m·s−1 is an SI derived unit, it could be viewed as more fundamental than the metre, since the latter is derived from the speed of light
Speed of light
The speed of light in vacuum, usually denoted by c, is a physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact since the length of the metre is defined from this constant and the international standard for time...

in a vacuum, which is defined as exactly 299 792 458 m·s−1 by the BIPM
International Bureau of Weights and Measures
The International Bureau of Weights and Measures , is an international standards organisation, one of three such organisations established to maintain the International System of Units under the terms of the Metre Convention...

. It follows that one metre is the length of the path travelled by light in a vacuum during a time interval of 1/299 792 458 of one second.

## See also

• Benz (unit)
Benz (unit)
A benz is a traditional German unit of velocity, equal to 1 metre per second.The name is in honor of Karl Benz, inventor of the gasoline-powered automobile....

• Kilometre per hour
• Orders of magnitude (speed)
Orders of magnitude (speed)
To help compare different orders of magnitude, the following list describes various speed levels between approximately 1 m/s and 3 m/s. Values in bold are exact.- List of orders of magnitude for speed :-See also:...

• Metre
Metre
The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...

• Second
Second
The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....

## External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL. 