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Homework Help: Statics Two objects with 3 angles

  1. Feb 26, 2009 #1
    1. The problem statement, all variables and given/known data

    Ok, Lets see, this problem consists of two (2) cars with a cable of unknown tension between them.

    The first car has a weight of 2100Kg and is at an angle of 10 degrees from the normal.
    The second car weighs 1360Kg and is at an angle of 26 degrees from the normal.

    There is a rope connecting them at an angle of 18 degrees from the normal.

    2. Relevant equations


    3. The attempt at a solution

    So far I have drawn a free body diagram that seems to be accurate. I have then divided the variables up into their respective coordinates

    Fy=0=N1sin(10)+N2sin(26)+ Tsin(18)-M1g-M2g

    I have been tinkering around with this and have been unable to come up with anything. I think that possibly the first car does not matter and only the second car matters because it is the weight and I can assume car 1 is fixed. If not that then possibly doing variable subsitution?

    Any Ideas?
  2. jcsd
  3. Feb 26, 2009 #2
    You speak of angles "from the normal" but you don't say what your reference is, what is this normal perpendicular to?

    By the way, if the unit is kg, then the quantity is a mass, not a weight. If it is a weight, it will be in Newtons.

    It would probably be a very good idea to post a figure for this problem. Also, you might want to try drawing (and posting) a FBD for each body.
  4. Feb 26, 2009 #3
    Ok let me try and get it uploaded.
  5. Feb 26, 2009 #4
    Ok here is the file, I couldn't just get the picture so I had to put up the entire file. It is problem 3.16. for my FBD I have a N1 and N2 perpendicular to each of the vechicles and a force of Mg straight down. and a force of -T from the truck and a force of T from the car. I don't have a scanner otherwise I would upload the FBD.
  6. Feb 26, 2009 #5
    I think the file is on this one.

    Attached Files:

  7. Feb 27, 2009 #6
    Looks like you need two FBDs, one for the crane and for the caisson. That should give you six equations, two translations and one rotation for each body. You have a little bit more work to do.
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