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!

Force on a collar

  1. Jan 23, 2007 #1
    1. The problem statement, all variables and given/known data

    Ok guys, me and a few buddy's are stuck on this one. We've got a smooth rod(BC)....and a collar(A) which is free to slide on it. I need to determine the Forces exerted on the collar by the cable, and by the rod....when a force F=900lb is applied to the collar. ***See pic.

    2. Relevant equations

    I'm not even sure where to start. I've only found the other angle to be 70 degrees.

    I think there is a tension and a compression force. I think the tension force this time is on the pipe....while the compression is on the cable. This seems weird....or not how it usually is....but I think its right.

    3. The attempt at a solution

    I've got the actual answers.....but would like to know how to get them....for test purposes.

    The answers say T=700lb(I think in the -20, or down direction).

    And....Fa = 1316lb (60 deg from the neg x side...upwards and to the left. ).

    Thanks for the help and for explaining

    View attachment Collar problem.bmp
  2. jcsd
  3. Jan 23, 2007 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    What do the other lines on your diagram represent? Could you state the question exactly as it's written please.
  4. Jan 23, 2007 #3
    Question as stated.......The collar A shown in fig3-7....is free to slide on the smooth rod BC. Determine the forces exerted on the collar by the cable and by the rod when the force F=900lb is applied to the collar.

    In the area left of B...is like a rock structure(no meaning)....and same as that to the right of C....and the cable(which attaches to the "rock on the right side" at pt D...which I forgot.) The xy axis goes right through center of the collar......and so does the Force.
  5. Jan 23, 2007 #4
    Is this understood now......or need more clearing up?
  6. Jan 24, 2007 #5
    We really need some help on this one guys....there are 3 of us, who don't understand it. Like I said....we've got the answers....just need cleared up, how to actually do it....so we can pass the tests!!! Thanks, and sorry for pushing so hard to get an answer.
  7. Jan 24, 2007 #6
    I have absolutely no idea what are you asking about... can you explain it more clearly...
    What is your force??? its direction??? etc...
  8. Jan 24, 2007 #7
    Okay.... I guess I understand your question now...

    There are 3 Forces act on the collar, which is F (act downward), tension form the cable
    (-20 degree to the right, and the normal force from the rod.. since the rod is frictionless, it
    must be perpendicular to the rod.....

    Do you know the vector notation? if yes, draw a free body diagram for this 3 force...
    You have enough equation for all the unknown... make your hand dirty and solve for
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?