Q. 31

# Estimate the speed of vertically falling raindrops from the following data. Radius of the drops 0.02 cm, viscosity of air = 1.8 × 10-^{4} poise, g = 9.9 × 10 m s^{-2} and density of water = 1000 kg m^{-3}.

Answer :

5 m s^{-1}

Given, radius of drops,

Viscosity,

Density of water,

Here, the viscous force is balanced by the weight.

Rate this question :

Is viscosity a vector?

Physics - ExemplarWater flows at a speed of 6 cm s^{-1} through a tube of radius 1 cm. Coefficient of viscosity of water at room temperature is 0.01 poise. Calculate the Reynolds number. It a steady flow?

Estimate the speed of vertically falling raindrops from the following data. Radius of the drops 0.02 cm, viscosity of air = 1.8 × 10-^{4} poise, g = 9.9 × 10 m s^{-2} and density of water = 1000 kg m^{-3}.

What is the largest average velocity of blood flow in an artery of radius 2 × 10^{–3}m if the flow must remain lanimar?

What is the corresponding flow rate? (Take viscosity of blood to be 2.084 × 10^{–3} Pa s).