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? asked in Science & MathematicsPhysics · 3 years ago

High school Physics?

A man lifts various loads with the same lever. The distance of the applied force from the fulcrum is 2.00 m and the distance from the fulcrum to the load is 0.500 m. A graph of resistance force vs. effort force is shown. What is the mechanical advantage of the lever? What is the ideal mechanical advantage of the lever? What is the efficiency of the lever? Show your work.

I know how to solve this problem but I'm having trouble identifying the forces and distances. I think the effort distance is 2.00 m and the resistance distance is 0.500 m. For the forces, would it be the forces at the very end of the line (of the graph below)? Can some please help me out?

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1 Answer

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  • ?
    Lv 7
    3 years ago
    Favorite Answer

    Mechanical Advantage is basically what factor your input force is increased by.

    MA = Fout/Fin

    [Where Fout is force applied to the load and Fin is force applied to the other end of the lever]

    Ideal Mechanical Advantage (IMA) for a lever is just the ratio of lengths either side of the fulcrum.

    The measured Mechanical Advantage (ie the measured Fout divided by measured Fin) is often known as Actual Mechanical Advantage (AMA) to distinguish from IMA.

    For a lever, efficiency is defined in terms of IMA and AMA.

    Efficiency = AMA/IMA

    ie, the fraction of the Ideal Mechanical Advantage that is actually applied to the load.

    # # # # #

    What is the [actual] mechanical advantage of the lever?

    AMA = (Force out)/(Force in)

    From the graph, force out is y and force in is x so we get

    AMA = 3.2x/x = 3.2

    What is the ideal mechanical advantage of the lever?

    IMA = 2.0/0.5 = 4

    What is the efficiency of the lever?

    Efficiency = AMA / IMA

    Efficiency = 3.2/4 = 0.8

    or if you like, 80% of an ideal lever

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