A simple Fluid Dynamics/Pressure HW question

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In summary, the conversation discusses using a hydraulic press with a small piston of cross-sectional area a and a larger piston of cross-sectional area A. The question asks for the force magnitude on the small piston that will balance a 41.8 kN force on the large piston. The solution involves using the equation P=F/A and correctly plugging in the values for the areas, rather than the diameters, to find the correct force magnitude of 2992.78N.
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Homework Statement


A piston of cross-sectional area a is used in a hydraulic press to exert a small force of magnitude f on the enclosed liquid. A connecting pipe leads to a larger piston of cross-sectional area A (the figure). If the piston diameters are 3.63 cm and 50.7 cm, what force magnitude on the small piston will balance a 41.8 kN force on the large piston?

Homework Equations


P=F/A

The Attempt at a Solution


So I'm pretty sure I'm doing this right especially since we did a similar one in class so I think it might just be a math error here's what I did.

For the smaller side Ps = Fs/as

For the larger side Pb = Fb/Ab

Ps = Pb

Fs/as = Fb/Ab

Solve for Fs
Fs = Fb/Ab * as

Plug in values (Fb 41.8kN = 41800N) (Ab 50.7cm =.507m) (as 3.63cm = .0363m)

Fs = (41800/.507)*.0363 = 2992.78N WileyPlus says its wrong though, so did I make a mistake?
 

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  • #2
For some reason you plugged in the diameters instead of the areas.
 
  • #3
paisiello2 said:
For some reason you plugged in the diameters instead of the areas.
I guess I did. I didn't even notice it said diameters thanks. I must remember to read more thoroughly next time.
 

FAQ: A simple Fluid Dynamics/Pressure HW question

What is the definition of fluid dynamics?

Fluid dynamics is the study of how fluids (liquids and gases) move and interact with their surroundings. It involves understanding the principles of motion, energy, and forces in fluids.

How do pressure and velocity affect fluid dynamics?

Pressure and velocity have a direct relationship in fluid dynamics. An increase in velocity leads to a decrease in pressure, and vice versa. This is known as Bernoulli's principle and is important in understanding the movement of fluids.

What is the difference between laminar and turbulent flow?

Laminar flow is smooth and orderly, with layers of fluid moving parallel to each other. Turbulent flow, on the other hand, is chaotic and irregular, with eddies and swirls. Turbulent flow occurs at higher velocities and is more common in real-world scenarios.

What are some real-life applications of fluid dynamics?

Fluid dynamics has numerous applications in our daily lives, including weather prediction, aerodynamics of airplanes, design of water systems and pipelines, and even blood flow in the human body. It is also crucial in industries such as oil and gas, automotive, and aerospace.

How is pressure calculated in fluid dynamics?

In fluid dynamics, pressure is calculated using the equation P = F/A, where P is pressure, F is the force acting on the fluid, and A is the area over which the force is applied. This equation is known as Pascal's law and is essential in understanding the behavior of fluids under different conditions.

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