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Homework Help: Dimensionalysis and Conversions

  1. Sep 9, 2007 #1
    1. The problem statement, all variables and given/known data

    Use the units given in the table below to determine whether the formulas are dimensionally consistent.

    / this symbol (to the left) means divided by

    Length= distance= m

    mass= Kg

    time= s

    area= m squared

    speed= m/s

    acceleration= m/s squared (only the s is squared)

    force= Kg m/s squared (only the s is squared)

    energy= Kg m squared /s squared

    power= Kg m squared /s cubed

    2. Relevant equations

    How do you solve these and how do you multiply the units?

    Does energy= (mass) (acceleration) (length)

    Does speed= acceleration/time

    Does area= (length) (length)

    Does energy= (mass) (speed squared)

    Does energy= (mass) (acceleration)/length

    3. The attempt at a solution

    I tried the first one.

    energy= (mass) (acceleration) (length)
    = [Kg] [m/s squared] [m]
    = [Kg m squared /s]

    Is that right?
  2. jcsd
  3. Sep 9, 2007 #2
    Does that answer match with the unit for energy, which you wrote earlier?

    Treat the units as you would ordinary numbers.
  4. Sep 9, 2007 #3
    So when I multiply the 2 m's and the 2 s's, they become squared right?

    The answer would then be Kg m squared /s squared.
  5. Sep 9, 2007 #4
  6. Sep 9, 2007 #5


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    Science Advisor

    Right! That's really all there is to it.
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