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प्रश्न
Calculate the viscous force acting on a raindrop of diameter 1 mm, falling with a uniform velocity of 2 m/s through air. The coefficient of viscosity of air is 1.8 × 10-5 Ns/m2.
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उत्तर
Given:
d = 1mm,
∴ r = `"d"/2 = 0.5` mm = 5 × 10-4 m
v0 = 2m/s,
η = 1.8 × 10-5 Ns/m2
To find:
The viscous force acting on the raindrop.
Solution:
Using Stokes’ law, the viscous force on the raindrop is
f = 6πηrv0
f = 6 × (3.142)(1.8 × 10-5)(5 × 10-4)(2)
f = 3.394 × 10-7 N
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