NTA Abhyas JEE Main2020PhysicsMechanical Properties of FluidsPractice
Glycerine is filled in 25 mm wide space between two large plane horizontal surfaces. A thin plate of area 0 .75 m 2 at a distance of 10 mm from one of the surfaces is in a horizontal position between the plates inside the glycerine. It is dragged horizontally at a constant speed of 0 .5 m s - 1 . Take coefficient of viscosity η = 0.5 N s m - 2 . What is the force required to drag the plate at a constant speed (in new
Correct answer
31.25
Step-by-step solution
F = ∑ η A d v d r = 0.5 × 0.75 0.5 10 × 10 - 3 0.5 15 × 10 - 3 = 0.5 × 0.75 × 0.5 × 10 3 1 10 + 1 15 = 0.5 × 0.75 × 0.5 × 10 3 ( 3 + 2 ) 30 = 31.25   N