Task: Text Categorization
Input (English): Mobility is related to the zeta potential, dielectric constant, and this quantity in the Smoluchowski equation. For gases, the variation of this quantity with temperature is given by Sutherland's formula. Measured with a Zahn cup, this quantity is squared in the Grashof number, and the ratio of this quantity to thermal diffusivity is the Prandtl number. When this quantity is zero, the Euler equations correspond to the NavierStokes equations. Reynolds number is the ratio of inertial forces to this quantity, which is constant for Newtonian fluids. Measured in poise [PWAHZ], this quantity is zero for superfluids. For 10 points, name this internal friction of a fluid that tends to resist its flow.
Output (English): Science