In fluid mechanics the Reynolds number is defined as Re = v D where is the density of…
PHYSICS · Multi-part · A Level · Physics · Measurements and their errors · Measurements and their errors
Problem
In fluid mechanics the Reynolds number is defined as
Re=ηρvD
where ρ is the density of the fluid, v is its speed relative to an object of characteristic length D, and η is the coefficient of dynamic viscosity.
(i) Show that the Reynolds number is a dimensionless quantity.
(ii) Hence obtain the dimensional formula of the coefficient of viscosity η and express it in both bracket notation and explicit power form.
(iii) State the SI unit of η that follows from your dimensional formula.