Question

A pipe of varying area of cross-section is held such that its axis is horizontal. At two cross-sections A and B, its radii are 8 cm and 4 cm. If velocity of water at A through the pipe is 16cm s^-1 and pressure at A is 106 dyne/cm2, find the pressure at cross-section B.​

Answer 1

Using A1v1 = A2v2

=> π(8)^2 × 16 = π (4)^2 v2

=> v2 = 64 cm s^-1 at cross section B

Now, since axis is horizontal, using Bernoulli's Theorem, we get

P2 + 1/2 ρv2^2 = P1 + 1/2 ρv1^2

=> P2 + 1/2 (64)^2 = P1 + 1/2 (16)^2 ...[ ρ= 1g cm^-3 for water]

=> P2 = P1 - 1/2 [64^2 - 16^2]

= 10^6 - 1/2 (64 + 16) (64- 16)

= 1000, 000 - 1920

= 99. 808 × 10^4 dyne/cm^2

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Answer 2

Answer:

The final answer is 99.808×10^4 dyne cm^2..

Hope it will be helpful ☺️ thank you!!