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Homework Help: Mass, Weight and the local acceleration due to gravity

  1. Jan 23, 2013 #1
    1. The problem statement, all variables and given/known data
    A person whose mass is 150lb weighs 144.4 lbf. Determine a) the local acceleration of gravity, in ft/s2, and b) the persons mass, in lb and weight, in lbf, if g = 32.174 ft/s2

    2. Relevant equations

    3. The attempt at a solution
    A) Using F=ma I got

    144.4 lbf = (150lb)a
    a = 0.963 ft/s2

    My answer seems kinda low. Am I missing something?

    b) F=ma

    mass = 150lb

    F = (150lb)(32.174 ft/sec2)
    F = weight = 4826 lbf

    I also feel like I'm missing something here as well, especially as it asks for the mass, which is already given. Am I misreading the question or something?

    Any help would be appreciated. Thanks
  2. jcsd
  3. Jan 23, 2013 #2


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    Science Advisor
    Homework Helper
    Gold Member

    Hint: if you'd been told the person weighed just a little more, 150 lbf, what would the answer have been?
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