Moderate

The pressure where the speed is doubled is

Correct answer: B. P-3/2ρV2

  • A. P+3/2ρV2
  • B. P-3/2ρV2
  • C. P+1/2ρV2
  • D. P-1/2ρV2

Explanation

According to Bernoulli's principle, for an incompressible, non-viscous fluid flowing at a constant height, an increase in fluid speed results in a decrease in pressure. When the speed is doubled, the change in pressure is quantified by subtracting 3/2 of the initial dynamic pressure (ρV2) from the original pressure P. Therefore, the correct answer is P-3/2ρV2. Options A and C suggest that pressure increases with speed, which is incorrect. Option D suggests a smaller decrease in pressure than what Bernoulli's principle dictates for a doubling of speed.

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About Fluid Dynamics

Fluid flow is described through speed, pressure and density, including steady flow and the equation of continuity for conserving mass. Bernoulli's equation relates pressure, speed and height, while fluid drag and terminal velocity explain why a falling object eventually moves at constant speed when drag balances its weight.

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