A raindrop of radius 0-2 mm falls through air- If the viscosity of air is 18 - 10-6 Pl- if the viscous drag acting on the drop when its speed is 1 ms-1 is 67-8 - 10-p newton- then find p

Radius of raindrop, a = 0.2 mm nbsp; nbsp; nbsp;=0.2× 10^ 3 m Air viscosity η =18× 10^ 6 Pl Speed of fall of raindrop, v=1 ms^ 1 From Stokes’ law Visco ...

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Standard XII

Physics

Friction

A raindrop of...

Question

A raindrop of radius 0.2 mm falls through air. If the viscosity of air is $18 \times 10^{- 6} P l,$ if the viscous drag acting on the drop when its speed is $1 m s^{- 1} is 67.8 \times 10^{- p}$ newton, then find p

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Solution

Radius of raindrop, a = 0.2 mm
$= 0.2 \times 10^{- 3} m$
Air viscosity $η = 18 \times 10^{- 6} P l$
Speed of fall of raindrop, $v = 1 m s^{- 1}$
From Stokes’ law
Viscous force $F = 6 π η a v$
$= 6 π \times 18 \times 10^{- 6} \times 0.2 \times 10^{- 3} \times 1$
$= 67.8 \times 10^{- 9} N$

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A raindrop of radius 0.2 mm falls through air. If the viscosity of air is 18×10–6 Pl, if the viscous drag acting on the drop when its speed is 1 ms–1 is 67.8×10–p newton, then find p

Radius of raindrop, a = 0.2 mm =0.2×10−3 m Air viscosity η=18×10−6 Pl Speed of fall of raindrop, v=1 ms−1 From Stokes’ law Viscous force F=6πηav =6π×18×10−6×0.2×10−3×1 =67.8×10−9 N

A raindrop of radius 0.2 mm falls through air. If the viscosity of air is $18 \times 10^{- 6} P l,$ if the viscous drag acting on the drop when its speed is $1 m s^{- 1} is 67.8 \times 10^{- p}$ newton, then find p

Radius of raindrop, a = 0.2 mm
$= 0.2 \times 10^{- 3} m$
Air viscosity $η = 18 \times 10^{- 6} P l$
Speed of fall of raindrop, $v = 1 m s^{- 1}$
From Stokes’ law
Viscous force $F = 6 π η a v$
$= 6 π \times 18 \times 10^{- 6} \times 0.2 \times 10^{- 3} \times 1$
$= 67.8 \times 10^{- 9} N$