1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Hydraulic brake system

  1. Nov 28, 2007 #1


    User Avatar

    1. The problem statement, all variables and given/known data
    The area of the piston in the master cylinder is 1.8cm^2, and that of the piston in the brake cylinder is 6.4cm^2. The coefficient of friction between shoe and wheel drum is .50. If the wheel has a radius of 34cm, determine the frictional torque about the axle when a force of 44N is exerted on the brake pedal.

    (Pedal)--[master cylinder]-----[brake cylinder]-----(shoe)Wheel drum

    2. Relevant equations

    F=(mu)*normal force


    3. The attempt at a solution

    I solved for F2 and got 12.4N. Is this the force that the shoe exerts on the wheel drum?
    If that is correct, how do i go about solving for the torque?

    thank you
  2. jcsd
  3. Nov 28, 2007 #2

    Shooting Star

    User Avatar
    Homework Helper

    You have to know where the force is being applied on the wheel. Since a radius is given, it seems logical to take the force as being applied at that ditance.

    Torque about a point = force*dist from that pt to line of action of force.
  4. Dec 27, 2007 #3
    I might be wrong, but I was going through the problem statement and got a doubt there.

    I think you have considered A1 as aan area of Master Cylinder, then F1 should be 44 N, as it is the force applied on the brake pedal. F2 must be a force exerted by a brake cylinder. Please correct me if my thinking is wrong...
  5. Dec 28, 2007 #4

    Shooting Star

    User Avatar
    Homework Helper

    Going through the problem again, I think user Chandrakiran is correct. Exerting 44 N and getting 12.4 N doesn't seem realistic. The OP had not specified which are the brake and master cylinders, and I had only anwered as to how to find the torque.

    Nice work, Chandrakiran.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Hydraulic brake system
  1. Braking system problem (Replies: 3)