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Ch. 13 - Fluids
Giancoli Douglas - Physics for Scientists and Engineers 5th edition
Giancoli Douglas5th editionPhysics for Scientists and EngineersISBN: 9780137488179Not the one you use?Change textbook
Chapter 13, Problem 51

Estimate the air pressure inside a category 5 hurricane, where the wind speed is 300 km/h (Fig. 13–56).
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1
Convert the wind speed from kilometers per hour (km/h) to meters per second (m/s) using the conversion factor: 1 km/h = 1000 m / 3600 s. This ensures the units are consistent with the SI system.
Apply Bernoulli's equation, which relates the pressure and velocity of a fluid. The equation is: P1 + 12ρv12 = P2 + 12ρv22, where P is pressure, ρ is air density, and v is velocity.
Assume the air pressure far from the hurricane (where the wind speed is negligible) is approximately atmospheric pressure, P1 = 1.01 × 105 \, Pa, and the air density is ρ = 1.2 \, kg/m3.
Rearrange Bernoulli's equation to solve for the pressure inside the hurricane, P2: P2 = P1 - 12ρv22, where v2 is the wind speed inside the hurricane.
Substitute the known values for P1, ρ, and v2 into the equation to calculate the air pressure inside the hurricane. Ensure all units are consistent before performing the calculation.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Air Pressure

Air pressure is the force exerted by the weight of air molecules above a given point. It is typically measured in units such as Pascals (Pa) or millibars (mb). In meteorology, lower air pressure is associated with storm systems, including hurricanes, where the pressure can drop significantly, leading to intense winds and precipitation.
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Hurricane Dynamics

Hurricanes are powerful tropical storms characterized by low-pressure centers, strong winds, and heavy rainfall. The wind speed in a hurricane is influenced by the pressure gradient between the center of the storm and the surrounding atmosphere. Understanding the relationship between wind speed and pressure is crucial for estimating the intensity and potential impact of a hurricane.
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Bernoulli's Principle

Bernoulli's Principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure. In the context of hurricanes, as wind speeds increase, the pressure within the storm's eye decreases. This principle helps explain why the central pressure of a hurricane is much lower than the surrounding areas, contributing to the storm's destructive power.
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