Question

A plate 0.025 mm distant from a fixed plate moves at 60 cm/s and requires a force of 2 N per meter square to maintain its speed. Determine fluid viscosity between the plates.

Answer 1

dy = 0.025 mm

= 0.025 × 10^-3m

Velocity of upper plate .

= 60 cm/s = 0.6 m/s

Force on upper plate

= 2(N/m²) = Shear stress, τ

du = change of velocity = u – 0 = 0.6 m/s

dy = change of distance = 0.025 × 10^-3m

Viscosity,

8.33 × 10^-5 (Ns/m²) = 8.33 × 10^-5 Pas