Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Metric conversion

  1. Feb 11, 2010 #1
    1. The problem statement, all variables and given/known data


    I have no idea how they got this answer. It says "doing the division gives you..." What division? It doesn't tell me what has been divided. The centimeters into grams? I can't find any plausible division that would give me .002 for an answer. I've been staring at this for an hour.
  2. jcsd
  3. Feb 11, 2010 #2


    User Avatar
    Gold Member

    It's basic dimensional analysis. The unit conversion factors used are:
    1 kg = 1000 g
    1 m= 100 cm thus 1 m3 = 1 x 106 cm3

    Multiply/divide the original expression by these factors so that the kg and m units cancel out and you'll get the answer shown.
  4. Feb 12, 2010 #3
    Thanks for the reply.
    I keep coming up with .02 as an answer, not .002. I must be setting up the multiplication/division equation wrong.
    I multiply the 1000g times 20kg to get 20,000g and divide it by 10^6 centimeters?
  5. Feb 12, 2010 #4


    User Avatar
    Gold Member

  6. Feb 12, 2010 #5


    User Avatar
    Homework Helper
    Gold Member

    I think you are doing it correctly. Problem with book's answer.
  7. Feb 12, 2010 #6


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook