Hydraulic piston break system problem

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SUMMARY

The hydraulic brake system problem involves a master cylinder piston area of 1.8 cm² and a brake cylinder piston area of 6.4 cm². When a force of 44 N is applied to the brake pedal, the correct frictional torque about the axle is calculated using the formula Tfrictional = 44(1.8/6.4) resulting in 2.1 N*m. The initial miscalculation of 26.6 N*m arose from an incorrect application of pressure distribution principles. Understanding the relationship between force, area, and torque is crucial for solving this problem accurately.

PREREQUISITES
  • Hydraulic systems fundamentals
  • Understanding of pressure distribution in fluids
  • Basic principles of torque calculation
  • Friction coefficients in mechanical systems
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  • Study the principles of Pascal's law in hydraulic systems
  • Learn about torque calculations in mechanical engineering
  • Explore the effects of friction in brake systems
  • Review fluid mechanics related to pressure and area relationships
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Mechanical engineers, automotive technicians, and students studying fluid mechanics or hydraulic systems will benefit from this discussion.

Thundagere
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Homework Statement



The figure below shows the essential parts of a hydraulic brake system. The area of the piston in the master cylinder is 1.8 cm2, and that of the piston in the brake cylinder is 6.4 cm2. The coefficient of friction between shoe and wheel drum is 0.50. If the wheel has a radius of 34 cm, determine the frictional torque about the axle when a force of 44 N is exerted on the brake pedal.

http://img690.imageshack.us/img690/2138/screenshot20121203at907.png

Homework Equations


This I'm honestly not sure about. I initially thought that because pressure is distributed evenly throughout all parts of the fluid, it should be

F1 / A1 = F2 / A2
But as my solution shows, apparently this is not the case

The Attempt at a Solution



I did
44 / 1.8 = F2 / 6.4
F2 = 156.4 N
Tfrictional = 156.4(0.5)(0.34) = 26.6 N *m

However, all of the answer keys state to do
44(1.8/6.4),
which results in the answer 2.1 N*m
Any help here? I'm really not sure what I'm doing wrong. THanks!
 
Last edited by a moderator:
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I agree with your result. (It would be crazy to have to push harder on the pedal than the resulting force on the brake shoe.)
 
Hmm... the problem statement vs the picture.
 
Last edited:

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