Metre per second

The metre per second (American English: meter per second) is an SI derived unit of both speed (scalar) and velocity (vector quantity which specifies both magnitude and a specific direction), defined by distance in metres divided by time in seconds.

The SI unit symbols are m·s−1, m s−1, m/s, or m/s,[1] sometimes (unofficially) abbreviated as mps. Where metres per second are several orders of magnitude too slow to be convenient, such as in astronomical measurements, velocities may be given in kilometres per second, where 1 km/s is 1000 metres per second, sometimes unofficially abbreviated as "kps".

Metre per second
Unit systemSI
Unit ofspeed
Symbolm/s or mps 
1 m/s in ...... is equal to ...
   km/h   3.6
   mph   2.2369
   knot   1.9438
   ft/s   3.2808


1 m/s is equivalent to:

= 3.6 km/h (exactly)[2]
≈ 3.2808 feet per second (approximately)[3]
≈ 2.2369 miles per hour (approximately)[4]
≈ 1.9438 knots (approximately)[5]

1 foot per second = 0.3048 m/s (exactly)[6]

1 mile per hour = 0.44704 m/s (exactly)[7]

km/h = 0.27 m/s (exactly)[8]

1 kilometre per second is equivalent to:

≈ 0.6213 miles per second (approximately)[9]
≈ 2237 miles per hour (approximately)[10]

Relation to other measures

The benz, named in honour of Karl Benz, has been proposed as a name for one metre per second.[11] Although it has seen some support as a practical unit,[12] primarily from German sources,[11] it was rejected as the SI unit of velocity[13] and has not seen widespread use or acceptance.[14]

See also


  1. ^ SI brochure, Section 5.1
  2. ^ CDX Automotive (2013). South African Automotive Light Vehicle Level 3. Jones & Bartlett Learning. p. 478. ISBN 1449697852.
  3. ^ Dinçer, İbrahim; Rosen, Marc A. (2007). EXERGY: Energy, Environment and Sustainable Development. Amsterdam: Elsevier. p. 444. ISBN 9780080531359. OCLC 228148217.
  4. ^ Jazar, Reza N. (2017). Vehicle Dynamics: Theory and Application (3. ed.). Cham, Switzerland: Springer. p. 957. ISBN 9783319534411. OCLC 988750637.
  5. ^ Collinson, R.P.G. (2013). Introduction to Avionics Systems (2. ed.). Boston: Springer Science & Business Media. p. 16. ISBN 9781441974662. OCLC 861706692.
  6. ^ Potter, Merle C; Wiggert, David C; Ramadan, Bassem H. (2016). Mechanics of Fluids, SI Edition (5. ed.). Cengage Learning. p. 722. ISBN 1305887700.
  7. ^ Das, Braja M.; Kassimali, Aslam; Sami, Sedat (2010). Mechanics for Engineers: Statics. Ft. Lauderdale, FL: J. Ross Publishing. p. 556. ISBN 9781604270297. OCLC 419827343.
  8. ^ Wright, Gus (2015). Fundamentals of medium/heavy duty diesel engines. Burlington, Massachusetts: Jones & Bartlett Publishers. p. 1349. ISBN 9781284067057. OCLC 927104266.
  9. ^ New Tritium Production Reactor Capacity Facilities, Siting, Construction and Operation: Environmental Impact Statement, Volume 4. United States. Dept. of Energy. 1991. p. 50.CS1 maint: others (link)
  10. ^ Hecht, Eugene (1999). Physique. Paris, France: De Boeck Superieur. p. 1263. ISBN 2744500186. OCLC 41495989.
  11. ^ a b Klein HA. (2011). The Science of Measurement: A Historical Survey. Dover Publications. p. 695. ISBN 978-0486258393.
  12. ^ Heijungs R. (2005). "On the Use of Units in LCA". The International Journal of Life Cycle Assessment. 10 (3): 174. doi:10.1065/lca2005.02.199.
  13. ^ Cardarelli F. (2004). Encyclopaedia of Scientific Units, Weights and Measures: Their SI Equivalences and Origins. Transl. by MJ Shields. (3rd revised ed.). Springer. p. 217. ISBN 978-1852336820.
  14. ^ Dresner S. (1974). Units of Measurement: An Encyclopaedic Dictionary of Units Both Scientific and Popular and the Quantities They Measure. Harvey Miller and Medcalf. p. 13. ISBN 978-0-85602-036-0.

External links


In physics, acceleration is the rate of change of velocity of an object with respect to time. An object's acceleration is the net result of all forces acting on the object, as described by Newton's Second Law. The SI unit for acceleration is metre per second squared (m⋅s−2). Accelerations are vector quantities (they have magnitude and direction) and add according to the parallelogram law. The vector of the net force acting on a body has the same direction as the vector of the body's acceleration, and its magnitude is proportional to the magnitude of the acceleration, with the object's mass (a scalar quantity) as proportionality constant.

For example, when a car starts from a standstill (zero velocity, in an inertial frame of reference) and travels in a straight line at increasing speeds, it is accelerating in the direction of travel. If the car turns, an acceleration occurs toward the new direction. The forward acceleration of the car is called a linear (or tangential) acceleration, the reaction to which passengers in the car experience as a force pushing them back into their seats. When changing direction, this is called radial (as orthogonal to tangential) acceleration, the reaction to which passengers experience as a sideways force. If the speed of the car decreases, this is an acceleration in the opposite direction of the velocity of the vehicle, sometimes called deceleration or Retrograde burning in spacecraft. Passengers experience the reaction to deceleration as a force pushing them forwards. Both acceleration and deceleration are treated the same, they are both changes in velocity. Each of these accelerations (tangential, radial, deceleration) is felt by passengers until their velocity (speed and direction) matches that of the uniformly moving car.

Cubic metre per second

A cubic metre per second (m3s−1, m3/s, cumecs or cubic meter per second in American English) is a derived SI unit of volumetric flow rate equal to that of a stere or cube with sides of one metre (~39.37 in) in length exchanged or moving each second. It is popularly used for water flow, especially in rivers and streams, and fractions for HVAC values measuring air flow.

The term cumec is also used, as shorthand for "Cubic metres per second", with the plural form cumecs also common in speech. It is commonly used between workers in the measurement of water flow through natural streams and civil works, but rarely used in writing. Data in units of cumec are used along the y-axis or vertical axis of a flow hydrograph, which describes the time variation of discharge of a river (the mean velocity multiplied by cross-sectional area). A moderately sized river discharges in the order of 100 cumecs.

Dimensionless quantity

In dimensional analysis, a dimensionless quantity is a quantity to which no physical dimension is assigned, also known as a bare, pure, or scalar quantity or a quantity of dimension one, with a corresponding unit of measurement in the SI of one (or 1) unit that is not explicitly shown. Dimensionless quantities are widely used in many fields, such as mathematics, physics, chemistry, engineering, and economics. Examples of quantities to which dimensions are regularly assigned are length, time, and speed, which are measured in dimensional units, such as metre, second and metre per second. This is considered to aid intuitive understanding. However, especially in mathematical physics, it is often more convenient to drop the assignment of explicit dimensions and express the quantities without dimensions, e.g., addressing the speed of light simply by the dimensionless number 1.

Foot per second

The foot per second (plural feet per second) is a unit of both speed (scalar) and velocity (vector quantity, which includes direction). It expresses the distance in feet (ft) traveled or displaced, divided by the time in seconds (s, or sec). The corresponding unit in the International System of Units (SI) is the metre per second.

Abbreviations include ft/s, ft/sec and fps, and the scientific notation ft s−1.

Foot per second squared

The foot per second squared (plural feet per second squared) is a unit of acceleration. It expresses change in velocity expressed in units of feet per second (ft/s) divided by time in seconds (s) (or the distance in feet (ft) traveled or displaced, divided by the time in seconds (s) squared). The corresponding unit in the International System of Units (SI) is the metre per second squared.Abbreviations include ft/s2, ft/sec2, ft/s/s, ft/sec/sec, and ft s−2.

ISO 31-1

ISO 31-1 is the part of international standard ISO 31 that defines names and symbols for quantities and units related to space and time. It was superseded in 2006 by ISO 80000-3.

Inch per second

The inch per second is a unit of speed or velocity. It expresses the distance in inches (in) traveled or displaced, divided by time in seconds (s, or sec). The equivalent SI unit is the metre per second.

Abbreviations include in/s, in/sec, ips, and less frequently in s−1.


The joule-second (J s, or J∙s) is the mathematical product of an SI Derived Unit, the joule (J), and an SI Base Unit, the second (s). The joule-second describes the amount of action occurring in a physical system through a summation of energy (or heat, or work) over time. In mathematical terms, this summation of energy means that the quantity of energy becomes integrated over time to give a number - an answer to the question.


m/s is the symbol for metre per second, a unit of both speed and velocity.

M/S or m/s may also refer to:

Motor ship, also MS, MV, M/V, or motor vessel, a maritime prefix

M/S stereo coding (Mid/Side stereo encoding), in audio engineering

Master/slave (BDSM)

Messrs., especially in India as a prefix to a firm or company name.

Metre per second squared

The metre per second squared is the unit of acceleration in the International System of Units (SI). As a derived unit, it is composed from the SI base units of length, the metre, and time, the second. Its symbol is written in several forms as m/s2, m·s−2 or m s−2, or less commonly, as m/s/s.As acceleration, the unit is interpreted physically as change in velocity or speed per time interval, i.e. metre per second per second and is treated as a vector quantity.

Metre squared per second

Metre squared per second or square meter per second is the SI derived unit of kinematic viscosity, specific relative angular momentum and thermal diffusivity. The unit is written in symbols as m2/s or m2·s−1 or m2s−1.

Newton (unit)

The newton (symbol: N) is the International System of Units (SI) derived unit of force. It is named after Isaac Newton in recognition of his work on classical mechanics, specifically Newton's second law of motion.

See below for the conversion factors.

Newton second

The newton second (also newton-second, symbol N s or N·s) is the derived SI unit of impulse. It is dimensionally equivalent to the momentum unit kilogram metre per second (kg·m/s). One newton second corresponds to a one-newton force applied for one second.

It can be used to identify the resultant velocity of a mass if a force accelerates the mass for a specific time interval.

Particle velocity

Particle velocity is the velocity of a particle (real or imagined) in a medium as it transmits a wave. The SI unit of particle velocity is the metre per second (m/s). In many cases this is a longitudinal wave of pressure as with sound, but it can also be a transverse wave as with the vibration of a taut string.

When applied to a sound wave through a medium of a fluid like air, particle velocity would be the physical speed of a parcel of fluid as it moves back and forth in the direction the sound wave is travelling as it passes.

Particle velocity should not be confused with the speed of the wave as it passes through the medium, i.e. in the case of a sound wave, particle velocity is not the same as the speed of sound. The wave moves relatively fast, while the particles oscillate around their original position with a relatively small particle velocity. Particle velocity should also not be confused with the velocity of individual molecules.

In applications involving sound, the particle velocity is usually measured using a logarithmic decibel scale called particle velocity level. Mostly pressure sensors (microphones) are used to measure sound pressure which is then propagated to the velocity field using Green's function.


The poncelet (symbol p) is an obsolete unit of power, once used in France and replaced by cheval vapeur (cv, metric horsepower). The unit was named after Jean-Victor Poncelet.One poncelet is defined as the power required to raise a hundred-kilogram mass (quintal) at a velocity of one metre per second (100 kilogram-force·m/s).

1 p

= 980.665 W = 11/3 cv (metric hp) = 1.315 hp (traditional horsepower)

Rate of climb

In aeronautics, the rate of climb (RoC) is an aircraft's vertical speed – the positive or negative rate of altitude change with respect to time. In most ICAO member countries, even in otherwise metric countries, this is usually expressed in feet per minute (ft/min); elsewhere, it is commonly expressed in metre per second (m/s). The RoC in an aircraft is indicated with a vertical speed indicator (VSI) or instantaneous vertical speed indicator (IVSI).

The temporal rate of decrease in altitude is referred to as the rate of descent (RoD) or sink rate.

A negative rate of climb corresponds to a positive rate of descent: RoD = -RoC.

Rayleigh (unit)

The rayleigh is a unit of photon flux, used to measure faint light emitted in the sky, such as airglow and auroras. It was first proposed in 1956 by Donald M. Hunten, Franklin E. Roach, and Joseph W. Chamberlain. It is named for Robert Strutt, 4th Baron Rayleigh (1875–1947). Its symbol is R (also used for the röntgen, an unrelated unit). SI prefixes are used with the rayleigh.

One rayleigh (1 R) is defined as a column emission rate of 1010 photons per square metre per column per second. Note that rayleigh is an apparent emission rate, as no allowances have been made for scattering or absorption. The night sky has an intensity of about 250 R, while auroras can reach values of 1000 kR.

The relationship between photon radiance, L, (in units of photons per square metre per second per steradian) and I (in units of rayleighs) is

SI derived unit

SI derived units are units of measurement derived from the seven base units specified by the International System of Units (SI). They are either dimensionless or can be expressed as a product of one or more of the base units, possibly scaled by an appropriate power of exponentiation.

The SI has special names for 22 of these derived units (for example, hertz, the SI unit of measurement of frequency), but the rest merely reflect their derivation: for example, the square metre (m2), the SI derived unit of area; and the kilogram per cubic metre (kg/m3 or kg m−3), the SI derived unit of density.

The names of SI derived units, when written in full, are in lowercase. However, the symbols for units named after persons are written with an uppercase initial letter. For example, the symbol for hertz is "Hz"; but the symbol for metre is "m".


In everyday use and in kinematics, the speed of an object is the magnitude of its velocity (the rate of change of its position); it is thus a scalar quantity. The average speed of an object in an interval of time is the distance travelled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero.

Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second, but the most common unit of speed in everyday usage is the kilometre per hour or, in the US and the UK, miles per hour. For air and marine travel the knot is commonly used.

The fastest possible speed at which energy or information can travel, according to special relativity, is the speed of light in a vacuum c = 299792458 metres per second (approximately 1079000000 km/h or 671000000 mph). Matter cannot quite reach the speed of light, as this would require an infinite amount of energy. In relativity physics, the concept of rapidity replaces the classical idea of speed.

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