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Homework Help: Retarding force

  1. Nov 13, 2007 #1


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    1. The problem statement, all variables and given/known data

    A car does 6.48E+4 J of work in traveling 2.92 km at constant speed. What was the average retarding force (from all sources) acting on the car?
    22.2 N

    2. Relevant equations

    F= w/d

    3. The attempt at a solution

    F= w/d

    6.48/ 2.92= 2.22 N ?
  2. jcsd
  3. Nov 13, 2007 #2


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    Staff Emeritus
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    Please pay attention to the units and exponent or powers of 10.

    6.48E+4 J = 64800 J

    2.92 km = 2920 m

    1 J = 1 N-m or 1 N = 1 J/m = 1 kg-m/s2
  4. Nov 13, 2007 #3


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    oooh, I had a feeling it had something to do with unit conversions, but the E threw me off. I guess I'm used to seeing 10^x. Thanks for pointing it out Astronuc.
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