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Standard XII

Physics

Terminal Velocity

A metal spher...

Question

A metal sphere of diameter $7 c m$ falls through a liquid of coefficient of viscosity $0.8 P a . s$ . When its velocity is $20 c m . s^{- 1}$ the viscous force acting on it is nearly ---- $N .$

0.11

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0.22

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Solution

The correct option is A $0.11$
Viscous force on the metal sphere = $6 π η r V$
$= 6 \times \times 0.8 \times \frac{3.5}{100} \times \frac{4}{3} π {(\frac{3.5}{100})}^{3} \times \frac{20}{100} N$
$= 0.1055 \approx 0.11 N$

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A metal sphere of diameter 7cm falls through a liquid of coefficient of viscosity 0.8Pa.s. When its velocity is 20cm.s−1 the viscous force acting on it is nearly ----N.

The correct option is A 0.11Viscous force on the metal sphere = 6πηrV=6××0.8×3.5100×43π(3.5100)3×20100N=0.1055≈0.11N

A metal sphere of diameter $7 c m$ falls through a liquid of coefficient of viscosity $0.8 P a . s$ . When its velocity is $20 c m . s^{- 1}$ the viscous force acting on it is nearly ---- $N .$

The correct option is A $0.11$
Viscous force on the metal sphere = $6 π η r V$
$= 6 \times \times 0.8 \times \frac{3.5}{100} \times \frac{4}{3} π {(\frac{3.5}{100})}^{3} \times \frac{20}{100} N$
$= 0.1055 \approx 0.11 N$