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Homework Help: Questions about units and conversion

  1. Apr 22, 2007 #1
    When you solve a problem and it wants the answer in non-SI units and they given you non-SI units, do you need to convert the non-SI units to SI units before you plug them into equations such as x=1/2gt^2. If you don't convert them into SI units, you'll get the answer wrong right?

    Basically, all the units need to math up in order for you to get the right answer?
  2. jcsd
  3. Apr 22, 2007 #2
    what is g in m/s^2? how many feet are in a meter? Now, do you think you need to convert it?
    Last edited: Apr 22, 2007
  4. Apr 22, 2007 #3


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    For something like that it shouldnt be a problem; i.e. if you are given g in ft/s2 and time in s, then x will be in ft. In general, you need to use units are compatible with each other, so you know the units of the thing you find in the end. If it's a more tricky calculation, then it may be easier to convert to the units you are familiar with (SI) to perform the calculation, so that then you know the correct units that the answr will be in, and then convert back. It's upto you.
  5. Apr 22, 2007 #4
    ok thanks. i just came across a problem that gave non SI units and asked you to give the answer in non SI units. I forgot to convert everything to the same units =[
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