Acceleration is the rate of change of an object's speed with respect to time. In other words, it is a measure of how speed changes over time. This article discusses acceleration units.
Mathematically speaking, acceleration ( ) is defined as the change in speed ( ) divided by the change over time ( ):
Where:
- is acceleration,
- is the change in speed,
- the change in time.
The International System of Units (SI) for acceleration is meters per second squared (m/s²) as the SI unit of acceleration. Since it is a vector, it can be expressed in any direction and can be positive or negative with increasing and decreasing acceleration.
There are many units used to measure acceleration around the world, but as mentioned above, the SI unit of acceleration is the most common unit of measurement for acceleration.
The standard unit of acceleration in the International System of Units (SI) is meters per second squared (m/s²). When an object's speed increases over time, it experiences positive acceleration; when it slows down, it experiences negative acceleration, often called deceleration.
In addition to linear acceleration, there is also angular acceleration. Angular acceleration is measured in radians per second squared (rad/s²). This is used when calculating rotational acceleration.
Some of the commonly used acceleration units are as follows:
Meters per second squared (m/s²):
The meter per second squared is the standard unit of acceleration in the International System of Units (SI). Represents the change in speed per second.
Kilometers per square hour (km/h²):
Although the kilometer per hour squared is not a standard SI unit, it is sometimes used in contexts where speed is measured in kilometers per hour. Represents the change in speed per hour.
G (gravity):
“g” is a unit of acceleration that corresponds to the acceleration of gravity, that is, approximately 9.8 m/s². It is often used in space travel and sports to express acceleration relative to the acceleration of gravity.
Feet per second squared (ft/s²):
The foot per second squared is a unit of acceleration in British and American measurement systems and represents the change in speed per second.
Gal (Galileo):
Gal is a unit of acceleration named after Galileo Galilei. A gallon is equal to 1 centimeter per second squared (cm/s²).
Inches per second squared (in/s²):
The unit inch per square second is used less frequently, but occurs in certain technical and physical applications.
Milligal (mGal):
A milligal is equal to one thousandth of a gallon and is often used in geophysics to express small accelerations related to gravitational fluctuations.
Parsecs per year squared (pc/year²):
In astronomy, this unit is used to express very small accelerations, especially in the study of celestial bodies.
Standard gravity (gn):
Standard gravity is a unit used in engineering and physics and corresponds to the acceleration of gravity. It is approximately 9.80665 m/s².
Knots per second (kn/s or kn²):
The knot per second is a unit of acceleration used in aviation and navigation that represents the change in speed per second.
Additionally, some other less common acceleration units are listed below.
Microgal (μGal):
A microgal is equal to one millionth of a gallon and is often used for precise measurements related to gravitational fluctuations.
Millimeters per second squared (mm/s²):
For very detailed measurements, a smaller unit of acceleration, the millimeter per second squared, is sometimes used.
Kiloparsec per megayear squared (kpc/Myr²):
This unit is used in astrophysics to express accelerations on an astronomical scale, particularly in the study of the dynamics of galaxies.
Earth gravitational unit (tgu):
The Earth's gravitational unit is used in geophysics and is defined as microgal. It is often used to express small fluctuations in the Earth's gravitational field.
Earth's surface gravity (g):
Earth's surface gravity is a unit to express the acceleration of gravity due to gravity on the Earth's surface; corresponds to 1 g or about 9.8 m/s².
These additional units provide more specialized ways of measuring acceleration and are tailored for specific applications in various scientific and engineering fields.
