Revolutions per minute

Revolutions per minute (rpm) measures rotational frequency as the number of complete turns made in one minute. It is commonly used to describe engines, motors, and rotating machinery.

Rotational frequency: The number of complete rotations an object makes per unit time. RPM is rotational frequency expressed using minutes as the time unit.
Tachometer: An instrument that measures the rotational speed of a shaft, engine, or other moving part. Tachometers commonly display rotational speed directly in rpm.
Revolutions per second: A rotational frequency unit counting complete turns in one second. It uses seconds instead of minutes, making its numerical value 60 times rpm.
Centripetal acceleration: The inward acceleration required to keep an object moving along a circular path. At a fixed radius, centripetal acceleration increases with the square of rotational frequency.
Angular velocity: The rate at which an object's angular position changes over time. It describes the same turning motion in angular units rather than turns per minute.
Engine speed: The rotational rate of an engine's crankshaft, commonly stated in revolutions per minute. RPM is the standard way to report how quickly an engine is turning.
Rotational speed: The rate at which an object turns about an axis. RPM is one conventional way to quantify rotational speed.
Centrifugal force: An apparent outward force used to describe motion in a rotating reference frame. Its apparent magnitude depends on rotational rate and distance from the axis.
Hertz: The SI unit of frequency, equal to one cycle per second. Hertz and rpm express frequency with different time bases; one hertz equals 60 rpm.
Spindle speed: The rotational rate of a machine-tool or other equipment spindle. Machine tools specify spindle speed in rpm to set cutting conditions.

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