Page 37 - ebook fluid mechanics_finalize

FLUID MECHANICS

Figure 3.6 : Large piston high than small
piston
p = p + 
gh ................ 5
2
1
Example 2

A force, P of 650 N is applied to the smaller cylinder of a hydraulic jack. The area, a of a
2
2
small piston is 15 cm and the area A of a larger piston is 150 cm .

Calculate the load, W can be lifted on the larger piston if :

(a) the pistons are at the same level

(b) the large piston is 0.65 m below the smaller piston

(c) the small piston is 0.40 m below the larger piston

3
3
Consider the mass density ρ of the liquid in the jack is 10 kg/m .

Solution :(Let see figure as show above)

a. if the pistons are at the same level

F W
Now P1 = and P2 =
a A
P1 = P2 ,

F = W Or F = W a
a A A

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