Viscosity, Stokes' law, terminal velocity, streamline and turbulent flow, critical velocity
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See all →- A spherical ball is dropped in a long column of a highly viscous liquid. The curve in the graph shown, which represents the speed of the ball (v) as a function of time (t) is : Answer: 3. B A ball dropped in a viscous liquid starts with acceleration g . As speed grows, viscous drag rises, so the acceleration falls t... 1
- The velocity of a small ball of mass M and density d, when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is d/2, then the viscous force acting on the ball will be : Answer: 1. Mg/2 Key idea: at constant (terminal) velocity the net force is zero: weight = buoyancy + viscous force. Volume of ball V=M/d . B... 1
- A small sphere of radius 'r' falls from rest in a viscous liquid. As a result, heat is produced due to viscous force. The rate of production of heat when the sphere attains its terminal velocity, is proportional to Answer: 2. r⁵ At terminal velocity, heat is produced at the rate equal to the power of the viscous force: P=F v_t=6πη r v_t² . Terminal velo... 1