Question

33. Two pistons push down on the fluid filling two cylinders connected by a narrow hose, as shown in the figure. The area A, is 1 square inch, and the area A. is 10 square inches. A force of 4 pounds is exerted downward on piston 1, as shown. (12 pts) 4 lb ! a) What is the pressure on A, (in psi)? b) What is the pressure on A. (in psi)? c) What is the force F, (in pounds) needed to keep piston 2 in place?

Answer 1

1) let F1 = 4 pounds

= 4*4.448 N (since 1 lb = 4.448 N)

= 17.8 N

A1 = 1 inch^2

= 1*(0.0254 m)^2

= 0.000645 m^2

pressure on A1, P1 = F1/A1

= 17.8/0.000645

= 2.76*10^4 Pa <<<<<<<-------------Answer

2) According to Pascal's law,

Pressure on A2 = Pressure on A1

= 2.76*10^4 Pa <<<<<<<<<----------------------Answer

3)
A2 = 10 inch^2

= 10*(0.0254 m)^2

= 0.00645 m^2

use, P2 = F2/A2

F2 = P2*A2

= 2.76*10^4*0.00645

= 178 N

= 178/4.448

= 40 lb <<<<<<<<<----------------------Answer