Dimensionless quantity
In dimensional analysis, a dimensionless quantity is a quantity to which no physical dimension is applicable.
It is thus a bare number, and is therefore also known as a quantity of dimension one.
Contents
Description
Dimensionless quantities are widely used in many fields, including:
Well-known dimensionless quantities include:
Cancellation of dimensionless and not-dimensionless
Dimensionless quantities are often obtained as products or ratios of quantities that are not dimensionless, but whose dimensions cancel in the mathematical operation.
This is the case, for instance, with the engineering strain, a measure of deformation. It is defined as change in length, divided by initial length, but because these quantities both have dimensions L (length), the result is a dimensionless quantity.
Quantities with dimensions
By contrast, examples of quantities with dimensions are length, time, and speed, which are measured in dimensional units, such as meter, second and meter/second.
See also
External links
- Dimensionless quantity @ Wikipedia
