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Homework Help: WORK-KE help?

  1. Apr 5, 2010 #1
    1. The problem statement, all variables and given/known data

    The 2008 dodge viper srt uses a v-10 engine to develop more than 600HP of the power,

    question- If the mass of the viper is 1560 kg, what work must be done by the car to accelerate from rest to 30m/s>

    2. Relevant equations

    I am confused on what formula to use

    3. The attempt at a solution

    I did.. KE=1/2mv^2.... so...1/2(1560KG)(30m/s)^2... is this correct?
  2. jcsd
  3. Apr 5, 2010 #2

    Out of interest, what other formulae do you have at your disposal?]

    edit: I didn't read your question properly, I do apologise.

    this is the energy transfer, not power.

    For power there are several equations available:

    [tex]W = F \cdot \Delta d [/tex]

    [tex]P(t) = F(t) \cdot v(t)[/tex]

    [tex]P = \frac{W}{\Delta s}[/tex]

    and also remember that horsepower can be converted to SI units of power.
    Last edited: Apr 5, 2010
  4. Apr 5, 2010 #3
    its a take home quiz... the formulas stated are... KE, PE, work, power and %lost

    i was hesitant because Joules obtained from the KE formula are not units of work? am i correct?
  5. Apr 5, 2010 #4
    That is correct, the units of work are Watts; [tex]W[/tex], or in other terms:


    [tex]kg \cdot m^{2} s^{-3}[/tex];

    [tex]N \cdot ms^{-1}[/tex]

    As you can see, all of these units involve a measurement of time, so are you sure there is not mention of time in the question?

    edit: you are confusing me haha; the units of work ARE joules, so the work done is the [tex]E_{k}[/tex]
    Last edited: Apr 5, 2010
  6. Apr 5, 2010 #5
    well ...

    part B of the question says... if the car does this work in a time of 4 seconds, what power did the car develop?
    could you use this on part A?
  7. Apr 5, 2010 #6
    haha, read my edits please =]
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