Rotational speed refers to the number of times an object rotates per unit time, and its dimension is angular unit/time unit, which is usually expressed in radian/second (rad/s), revolutions per minute (rpm) and other units, where radian/second is an international standard unit of measurement and a kind of SI. It may not be easy to understand that the circumference is used alone every second, but it usually has a simple mathematical relationship with revolutions per minute, such as1rpm = 2π/60 rad/s.
Rotational speed is a very important physical quantity, which is widely used in machinery, engineering, physics and other fields. For example, in the process of machining, rotational speed is one of the most important parameters to control the cutting effect and safety of tools.