1. Units and Dimensions
Completion requirements
Secondary Dimension and Units
Secondary dimensions are derived from the combination of primary dimensions.
| Secondary Dimension | Symbol | SI Unit | English Unit |
|---|---|---|---|
| Velocity | \(v\) | m/s | ft/s |
| Acceleration | \(a\) | m/s\(^2\) | ft/s\(^2\) |
| Volume | \(V\) | m\(^3\) | ft\(^3\) |
| Force | \(F\) (\(= ma\)) | N (Newton) | lb\(_f\) (pound-force) |
| Pressure | \(P\) (\(= F/A\)) | N/m\(^2\) | lb\(_f\)/in\(^2\) (psi) |
| Energy, Work | \(E\) (\(= Fd\)) | J (Joule = N.m) | ft.lb\(_f\) |
| Power | \(P\) | W (= J/s) | ft.lb\(_f\)/s |
Note that there are many other units, both SI and English, in use today. For example, power is often expressed in units of horsepower, in addition to the standard units of watt. There are conversion factors to enable conversion from any of these units to any other.