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    • Thread Starter
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    Need help with 4i.

    Don't really understand it.

    I did :
    Initial Ke + Inital GPE = Final KE + Finial GPE + wd by friction
    160 + 0 = 1000+ 6703 + 1750
    Is the work done just supposed to be on the left of the equation as both have to be equal?
    Also is it always (+) wd by friction?

    https://9565af48d144678aee5dbc2a15d4...20M2%20OCR.pdf
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    (Original post by Super199)
    Need help with 4i.

    Don't really understand it.

    I did :
    Initial Ke + Inital GPE = Final KE + Finial GPE + wd by friction
    160 + 0 = 1000+ 6703 + 1750
    Is the work done just supposed to be on the left of the equation as both have to be equal?
    Also is it always (+) wd by friction?

    https://9565af48d144678aee5dbc2a15d4...20M2%20OCR.pdf
    Your equation doesn't take into account the pulling force. You're not actually looking for an equation as such, rather a formula for the work done by the pulling force.

    If we start with a more general formula.

    "Work done by pulling force" = "gain in energies of object" + "work done against friction"

    = "final KE - initial KE" + "final GPE - initial GPE" + "work done against friction"

    And take it from there.
 
 
 
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