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InterviewSolution
| 1. |
What is strokes law? |
| Answer» According to Stokes law the backward viscous force acting on a small spherical body of radius R are moving with a uniform velocity V through fluid of viscosity neta is given by :- F =6nπrv<br>It is a law that predicts the frictional force on a spherical body falling through a viscous medium (like oil), under the influence of gravity. We have,F=6pie ×n× r×vWhere r=radius of the falling sphere,v= instantaneous velocity and n Is the viscosity of the medium The sphere accelerates until it reaches a steady terminal speed, i.e., when F is equal to the gravitational force on the sphere.<br>The viscous drag force (f) on the sphere of radius (r) moving with the velocity(v) through the fluid of viscocity(n) is F=6πnrv<br>\tThe force that retards a sphere moving through a viscous fluid is directly ∝to the velocity and the radius of the sphere, and the viscosity of the fluid.\tMathematically:-F =6πηrv where\tLet retarding force F∝v where v =velocity of the sphere\tF ∝ r where r=radius of the sphere\tF∝η where η=coefficient of viscosity\t6π=constant\tStokes law is applicable only to laminar flow of liquids.It is not applicable to turbulent law. | |