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Homework Help: Calculate forces on a double scissor jack

  1. Mar 10, 2017 #1
    1. The problem statement, all variables and given/known data
    Find maximum forces in one given jack assembly. If I don't make it any easier, I will have 15 unknown forces, so I tried to just take the weight forces at the top...is it an okay assumption? If not, what should I do? My attempt on a solution is underneath. Thanks for tips and answers.
    2. Relevant equations
    They are given in the picture below.

    3. The attempt at a solution
  2. jcsd
  3. Mar 12, 2017 #2


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    Science Advisor
    Gold Member

    There have to be balancing forces somewhere - the stand as shown would just collapse .

    Do you want to work out the forces in each link or just the ratio between input force and lifting force ?

    Have you seen this earlier thread ?
    Last edited: Mar 12, 2017
  4. Mar 12, 2017 #3
    I'm sorry, I have a motor that holds the bar between the jacks together, so it is a force F holding the lower right leg in place. I'm most interested in finding where and how big the maximum stress is, so I can choose the right cross section for it.
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