Final answer:
The Reynolds number is a dimensionless quantity used to determine laminar or turbulent flow in fluid mechanics.
Step-by-step explanation:
The Reynolds number (NR) is a dimensionless quantity used in fluid mechanics to determine whether the flow of a fluid is laminar or turbulent. It is calculated using the equation NR = (p * v * r) / n, where p is the fluid density, v is the fluid speed, n is the fluid viscosity, and r is the radius of the tube. By substituting the units for each quantity in the equation and canceling them out, we can show that the Reynolds number is unitless. For NR values below 2000, the flow is laminar, while for NR values above 3000, the flow is turbulent.