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Mistakes in book??Please help with question...I'm going crazy watch

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    Answers said to be:
    Q3
    A) 50J

    B) i= 75%
    ii= 76%
    iii= 76%

    C) 30J
    Thank you so much
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    (Original post by Kirk16)
    Answers said to be:
    Q3
    A) 50J

    B) i= 75%
    ii= 76%
    iii= 76%

    C) 30J
    Thank you so much
    This is a very poorly worded question.

    The diagram appears to show only the energy output in the form of heat, sound and kinetic energy of the door movement.

    It is not at all clear what the energy input to the system is because that is not stated (it's entirely missing) in the question.

    Without that vital piece of information, the efficiency of the system/components cannot be calculated. The whole question is therefore meaningless as it stands.
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    Hi Uberteknik,
    It is said the total input is 50J.
    I hope you can help...



    QUOTE=uberteknik;68292316]This is a very poorly worded question.

    The diagram appears to show only the energy output in the form of heat, sound and kinetic energy of the door movement.

    It is not at all clear what the energy input to the system is because that is not stated (it's entirely missing) in the question.

    Without that vital piece of information, the efficiency of the system/components cannot be calculated. The whole question is therefore meaningless as it stands.[/QUOTE]
 
 
 
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