UNIT 4
Density and Pressure
Example 1
Example 2
Example 3
Example 4
Example 5
Example 6
Example 7

 

Density and Pressure in Fluids
Example 3

example1

(a) At 10000m the external air pressure is 24 kPa, but the pressure inside the airliner is 75kPa to allow the passengers to breathe comfortably. What is the net outward force pushing on a window of area 0.05m2?
(b) Air flowing in a streamline manner can cause changes in pressure. What would be the force on a windshield with dimensions 2.0m X 1.0m if the pressure inside remains at atmospheric (105kPa) and outside pressure decreased to 95kPa?.

What

External air pressure is 24 kPa
Internal air pressure is 75 kPa
Area of window = 0.05m2

Force on outside of window = External Pressure X Area of window
Force on outside of window = 24 kPa X 0.05m2
Force on outside of window = 1.2 kN
Force on inside of window = Internal Pressure X Area of window
Force on inside of window = 75 kPa X 0.05m2
Force on inside of window = 3.75 kN
Net Force = 3.75 kN - 1.2 kN
Net Force = 2.55 kN

External air pressure is 95 kPa
Internal air pressure is 101 kPa
Area of windshield = 2.0m2
Force on outside of windshield = External Pressure X Area of window
Force on outside of windshield = 95 kPa X 2.0m2
Force on outside of windshield = 190 kN
Force on inside of windshield = Internal Pressure X Area of window
Force on inside of windshield = 101 kPa X 2m2
Force on inside of windshield = 202 kN
Net Force = 202 kN - 190 kN
Net Force = 12.0kN

   
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Concept by Kishore Lal. Programmed by Kishore Lal... Copyright © 2015 Kishore Lal. All rights reserved.