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Thread: Forces Equillibrium Problem

  1. #1 Forces Equillibrium Problem 
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    Determine the maximum weight of the flowerpot that can be supported without exceeding a cable tension of 50 lb in either cable AB or AC. Note that the 2 cables make an angle 60 and 53.1 respectively with the horizontal

    Fxnet=TABcos60-TACcos53.1 =0
    Fynet-TABsin60+TACsin53.1-W=0
    I dont know how to figure out if 50lb is the tension in cable AB or in AC
    does the more vertical cable have the higher tension why?


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  3. #2  
    Forum Masters Degree organic god's Avatar
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    can we have a diagram please


    everything is mathematical.
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  4. #3  
    Forum Masters Degree bit4bit's Avatar
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    If the forces are in equillibrium, then it looks to be a setup where A is the position of the plantpot, which is supended by two ropes to points B and C.

    Labelling AB as T<sub>1</sub>, and AC as T<sub>2</sub>:

    x: 0=T<sub>1</sub>cos120 + T<sub>2</sub>cos53.1
    y: W=T<sub>1</sub>sin120 + T<sub>2</sub>sin53.1

    Calculate the angles, and solve simultaneously for (say) T<sub>1</sub>. Then plug in 50lb for T<sub>1</sub>, and calculate W. Do the same for T<sub>2</sub>, and calculate W again. The lowest W value should be the maximum weight of the plantpot.
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  5. #4 Re: Forces Equillibrium Problem 
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    Quote Originally Posted by myoplex11
    Determine the maximum weight of the flowerpot that can be supported without exceeding a cable tension of 50 lb in either cable AB or AC. Note that the 2 cables make an angle 60 and 53.1 respectively with the horizontal

    Fxnet=TABcos60-TACcos53.1 =0
    Fynet-TABsin60+TACsin53.1-W=0
    I dont know how to figure out if 50lb is the tension in cable AB or in AC
    does the more vertical cable have the higher tension why?
    If you rearrange your first equation you find that the ratio of TAB to TAC is cos53.1/cos60, which means that TAB is 1.2 times TAC. Therefore AB has to be the one with 50 lb tension, and this is the more vertical cable.
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