# A straight $100 \mathrm{~m}$ long raw water gravity main is to carry water from an intake structure to the jack well of a water treatment plant. The required flow through this water main is $0.21 \mathrm{~m}^{3} / \mathrm{s}$. Allowable velocity through the main is $0.75 \mathrm{~m} / \mathrm{s}$. Assume $\mathrm{f}=0.01, \mathrm{~g}=9.81 \mathrm{~m} / \mathrm{s}^{2}$. The minimum gradient (in $\mathrm{cm} / 100 \mathrm{~m}$ length) to be given to this gravity main so that the required amount of water flows without any difficulty is

## Question ID - 156055 :- A straight $100 \mathrm{~m}$ long raw water gravity main is to carry water from an intake structure to the jack well of a water treatment plant. The required flow through this water main is $0.21 \mathrm{~m}^{3} / \mathrm{s}$. Allowable velocity through the main is $0.75 \mathrm{~m} / \mathrm{s}$. Assume $\mathrm{f}=0.01, \mathrm{~g}=9.81 \mathrm{~m} / \mathrm{s}^{2}$. The minimum gradient (in $\mathrm{cm} / 100 \mathrm{~m}$ length) to be given to this gravity main so that the required amount of water flows without any difficulty is

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Answer Key : (4.7 to 4.9) -

4.7 to 4.9

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For a symmetric airfoil, the lift coefficient for zero degree angle of attack is
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(B) 0.0
(C) 0.5
(D) 1.0 