1. Fluid Pressure and Fluid Force
Lesson 7.7

2. Fluid Pressure Definition: The pressure on an object at depth h is
Where w is the weight-density of the liquid per unit of volume
Some example densities water lbs/ft3 mercury 849 lbs/ft3

3. Fluid Pressure
Pascal's Principle: pressure exerted by a fluid at depth h is transmitted equally in all directions
Fluid pressure given in terms of force per unit area

4. Fluid Force on Submerged Object
Consider a rectangular metal sheet measuring 2 x 4 feet that is submerged in 7 feet of water
Remember so P = 62.4 x 7 = 436.8
And F = P x A so F = x 2 x 4 = lbs

5. Fluid Pressure
Consider the force of fluid against the side surface of the container
Pressure at a point
Density x g x depth
Force for a horizontal slice
Density x g x depth x Area
Total force

6. Fluid Pressure The tank has cross section of a trapazoid
Filled to 2.5 ft with water
Water is 62.4 lbs/ft3
Function of edge
Length of strip
Depth of strip
Integral
(-4,2.5)
(4,2.5)
2.5 - y
(-2,0)
(2,0)
y = 1.25x – 2.5 x = 0.8y + 2
2 (0.8y + 2)
2.5 - y

7. Assignment
Lesson 7.7
Page 511
Exercises 1-25 odd