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Homework Help: Potential energy in fuels

  1. Apr 7, 2009 #1
    1. The problem statement, all variables and given/known data
    A fully charged 15.0 kg lead-acid battery can deliver power 1450 W for 1.0 hr. (For comparison, the "heat of combustion" of gasoline is about 44 MJ/kg.)

    Battery _____ MJ/kg

    2. Relevant equations
    Unit conversion problem
    1W = 1 J/s

    3. The attempt at a solution
    (1450 J/s / 15kg) = 96.7/10^6 = 9.6 *10^-5
  2. jcsd
  3. Apr 7, 2009 #2


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    Gold Member

    You should notice immediately if you kept your units that your final answer does not have the units of MJ/kg as I see your answer requires. Remember, Watts (or Power) is a unit of energy per time. You're missing one part of the calculation.
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