# Power number

The

**power number** N

_{p} (also known as Newton number) is a

dimensionless number
relating the

resistance force to the

inertia force. In

engineering, this number, along with the

Reynolds number, is one of the most widely employed dimensionless numbers.

The power-number has different specifications according to the field of application. E.g., for
stirrers the power number is defined as:

with