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Car Braking

  1. Jan 25, 2009 #1
    1. The problem statement, all variables and given/known data

    How much pressure must be exerted by the braking system of a car weighing 3000 lb, if you want to stop it from 40 mph to 0 in 1.5 seconds? Assume the total braking surface of the four wheels is 96 in^2. How much force must be exerted by your foot on the brake pedal in the absence of a vacuum assist, if the brake cylinder diameter is 3/4 inch?

    2. Relevant equations

    Am I supposed to know something about cars to answer this? I don't understand how to even start this problem.

    3. The attempt at a solution
  2. jcsd
  3. Jan 25, 2009 #2


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    What equation link force, mass and accelration?
    What do you know about the ratio of cylinders in hyraulics?
  4. Jan 25, 2009 #3
    so I can use F=ma and V= V_initial + a*t by rearranging and coming up with
    F=(m*Delta V)/t ?

    As to your second question, I haven't learned anything about the ratio of cylinders or hydraulics. What is the ratio?
  5. Jan 25, 2009 #4


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