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Homework Help: Need help on the acceleration

  1. Oct 21, 2004 #1

    bem

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    my pre-test has a question: "A man is standing on a balance scale which reads 80kg. Suddenly, he quats with a n acceleration a (downward). What weight does the scale read while the man is squatting?
    (A)the same (B) more than 80kg (c) less than 80kg

    I chosed (b)
    because before we have N=mg
    then after the man squatting N=m(g+a)
    so the scale has to read more than 80kg. But then one of my friend said that N=m(g-a). I'm just confused. Can smbd help me ? I have a bet with him ( 10 bucks, hehe).
     
  2. jcsd
  3. Oct 22, 2004 #2

    Tide

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    Bem,

    Consider the ultimate squat. What if the man squatted REALLY fast - i.e. he lifts his legs up off the scale and free falls. What would the scale read in that case?
     
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