https://doi.org/10.1351/goldbook.S06028
\(F=6\ \pi \ \eta \ r\ \nu\), where \(F\) is the force exerted on a sphere of radius \(r\) which is moving through a fluid of @V06627@ \(\eta \) with a relative velocity \(\nu\); this equation holds at low velocities which are free from turbulence (called the @S06027@ region).