Question

A flat plate of side 20 cm moves over another similar plate with a thin layer of 0.4 cm of a liquid between them. If a force of one kg wt. moves one of the plates uniformly with a
velocity of 1m/s, calculate the coefficient of viscosity.​

Answer 1

Answer:

η = 0.98 Pa sec

Explanation:

Given :

Side of plate = 20 cm

= > Area of plate = 20 × 20 = 400 cm²

Area in term of m² :

= > Area = 400 × 10⁻⁴ m²

Force = 1 kg wt = 9.8 N

d v = 1 m / sec

d x = 0.4 cm

We know :

η = F / A ( d v / d x )

η = 9.8 × ( 0.4 × 10⁻² ) / 400 × 10⁻⁴ × 1

= > η = 9.8 × ( 0.4 ) / 400 × 10⁻² × 1

= > η = 9.8 × ( 0.4 ) / 4

= > η = 0.98 Pa sec

Therefore , we get required answer.