Equilibrium of pistons with different radii (Hydraulics)

[Z3nt4r0]

Homework Statement

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Homework Equations

Force exerted by liquids
F=h.d.g.A

The Attempt at a Solution

 

[phyzguy]

If the radius of piston B is 4 times the radius of piston A, how much larger is the area of piston B than piston A?

 

[Z3nt4r0]

If the radius of piston B is 4 times the radius of piston A, how much larger is the area of piston B than piston A?

4 times?

 

[phyzguy]

4 times?

No.

 

[Z3nt4r0]

No.

16?

 

[phyzguy]

16?

Yes, but can you explain why?

 

[Z3nt4r0]

Yes, but can you explain why?

I am not quite sure so I guess not. Can you explain me how to solve the problem?

 

[phyzguy]

Your approach was right, you just got the areas wrong. You should go back and review how to calculate the area of a circle.

 

[Z3nt4r0]

Your approach was right, you just got the areas wrong. You should go back and review how to calculate the area of a circle.

I just realized that pistons were cylindrical lol

So while piston A has an area of Pi number x r^2 piston B has an area of Pi number x 4r^2

If, for example, radius of piston a is 1, piston b's radius will be 4, making piston b's area 16 times bigger than piston a's.

So the answer to the question is 16. Am I right now?

 

[Chestermiller]

What are h, d, and g in your equation?

 

[Z3nt4r0]

What are h, d, and g in your equation?

Height, density, and gravity.

 

[Chestermiller]

Do you really think that the pressure within the closed horizontal system shown in the figure is hydrostatic?