RPM
- Alternate uses: rpm (disambiguation)
An acronym for 'revolutions per minute', rpm is a unit of frequency, commonly used to measure rotational speed.
- Gramophone records typically rotate with 33, 45, or 78 rpm.
- An automobile's engine typically makes between 700 and 7000 rpm.
- Aircraft piston motors can rotate with 8000 rpm.
- A racing car engine's limits are much higher, as high as 19,000 rpm in Formula 1.
- Gas turbine engines rotate at tens of thousands of rpm.
- A computer's hard drive can range from 3000-7200 RPM on IDE types and from 10-25,000 on SATA and SCSI drives.
- A 52x CD-ROM drive can rotate a cd as fast as 32,000 RPM.
Standards bodies generally recommend the symbol 'r/min', which better follows the general principles for forming unit symbols.
The SI unit of frequency is the hertz (Hz):
- 1 rpm = 1 r/min = 1/60 Hz
The SI unit of angular speed is the radian per second:
- rotational speed = 1 rpm = 1 r/min ( = 1/60 Hz) = 2π rad/min = 2π/60 rad/s = 0.104 719 76 rad/s = angular speed
See also
