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Effort/ Load simple machines question

  1. Oct 2, 2011 #1
    1. The problem statement, all variables and given/known data
    A screw jack that is used on cars whenever tyres are changed by the owner. The screw moves though a distance equal to its pitch whenever the effort lever ( jack handle) is given a complete turn. If the length of the jack handle is 24cm, the pitch is 2mm and the jack is required to lift a 900kg vheicle. Assuming efficiency is 100%. calculate the Effort reqired to lift the car.

    Given Length of 24cm
    Pitch of 2mm
    Mass of 900kg
    100% efficiency

    2. Relevant equations
    Velocity ratio
    Mechanical advantage

    3. The attempt at a solution

    VR = 2
    MA = L/E


  2. jcsd
  3. Oct 2, 2011 #2
  4. Oct 4, 2011 #3
    no help for this?

    I've also assumed as the handle of 24cm goes around 1 complete turn, the jack goes up 2mm. Also gravity on the 900kg of the Load.

    But its so confusing. And I'm new to physics can someone help me..
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