Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Lever system - brake (counting of forces)

  1. Nov 6, 2012 #1
    Hello.
    I tried to solve this question:
    3586m3n.jpg
    So F1D1=F2D2. Thus:
    60N/ 0,06m x 0,2 m= f/0,02m x 0,04m
    =100 Newton applied to the piston, but this doesn't fit to the answers offered.
    What did I wrong?:(
     
  2. jcsd
  3. Nov 6, 2012 #2
    Why are you dividing the 60 N force by 6 cm?
     
  4. Nov 6, 2012 #3
    Because it applies some force on the area, isnt it?

    It's so easy, that I just need to divide 60N by 0,2M?
     
  5. Nov 6, 2012 #4
    I think you are mixing the lever rule with the hydraulic press (Pascal principle).
    The question is about forces. You don't need pressures. And dividing by 6 cm will not give pressure anyway (it's piston's diameter not its area).
    Are there more questions related to the same diagram?
     
  6. Nov 6, 2012 #5
    No, only this one.
    Have you managed to solve it?
     
  7. Nov 6, 2012 #6
    Use the equation for the lever or just equilibrium of torques around the pivot.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook