1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Statics: Equilibrium of Machines

  1. Oct 22, 2005 #1
    The problem is stated in the picture. And I drew the FBDs of the top half of the bolt cutter, as shown in the second page:

    Setting moment about A to be 0, I obtain -Q(1 in)-FBy*4 in=0
    And By= -Q/4 lb

    Then setting moment about C to be zero. I obtain
    FBy(0.5 in)-20 in(75 lb)=0
    Substitute in By, I get the magnitude of Q to be 12000 lb.

    http://img368.imageshack.us/img368/7535/1239zw.jpg [Broken]
    http://img368.imageshack.us/img368/431/22cm.jpg [Broken]

    Am I correct?

    Attached Files:

    • 2.jpg
      File size:
      54.6 KB
    • 123.jpg
      File size:
      46.5 KB
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Oct 22, 2005 #2


    User Avatar
    Homework Helper

    What was the problem then?, it looks good to me (the procedure, i didn't do the arithmetic).
  4. Oct 23, 2005 #3
    The problem just seems...too easy...
  5. Oct 23, 2005 #4


    User Avatar
    Homework Helper

    I was checking the problem again you forgot the Bx component when you did moment about C, it does have a moment, and the lever arm for 75 about c is 19.5
  6. Oct 27, 2005 #5
    AE is 2-force member (so the reaction at A is only Ay), so that Bx is actually zero (due to the equilibrium eqs of AB). Then you can solve the rest of them.
    Last edited: Oct 27, 2005
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook