JEE Mains · Physics · STD 11 - 9.1 fluid mechanics
The velocity of upper layer of water in a river is \(36 kmh ^{-1}\). Shearing stress between horizontal layers of water is \(10^{-3} Nm ^{-2}\). Depth of the river is \(m\). (Co-efficiency of viscosity of water is \(10^{-2} \,Pa . s\) )
- A \(500\)
- B \(107\)
- C \(700\)
- D \(100\)
Answer & Solution
Correct Answer
(D) \(100\)
Step-by-step Solution
Detailed explanation
\(F =\eta A \frac{\Delta v _{ x }}{\Delta y }\) \(\frac{ F }{ A }=\eta \frac{\Delta v _{ x }}{\Delta y }\) \(\Rightarrow 10^{-3}=10^{-2} \times \frac{36 \times 1000}{ h \times 3600}\) \(\Rightarrow h =10^{-2} \times \frac{36 \times 1000}{10^{-3} \times 3600}=100 \,m\)
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