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Homework Help: Need help on conversion factors (physics)

  1. Sep 3, 2010 #1
    Hello, new to this place. Started physics the other day in high school and already have homework. Not really good with conversion factors, so would like some help with a few of the problems i had 4 homework.

    1.) Suppose your hair grows at the rate of 1/30 inch per day. Find the rate at which it grows. Because the distance between atoms in a molecule is on the order of 0.1 nm, your answer suggests how rapidly atoms are assembled in this protein synthesis.

    I was thinking on changing inches to nanometers or whaterver NM means. Dont really know what 2 do after that.

    2.)A rectangular building lot is 1.20*10^3 ft by 1.60*10^2 ft. Determine the area of this lot. Answer says its in m^2.

    This is what i did so far. First one came out to 1200ft, and the other number comes out to 160ft. I know i multiply them to get the area, but how do i convert the answer to meters squared.
  2. jcsd
  3. Sep 3, 2010 #2


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    Welcome to Physics Forums :smile:

    Hmm, well that is a weird thing to ask since we are told the rate to begin with: it's 1/30 inches per day! Are you quoting the question exactly? Is there reason to think they expect a conversion to metric units?

    Yes, nm means nanometers. You could certainly do that, though I don't see what, in the question, says you must.

    It's probably easiest, conceptually, to convert each foot value into meters first. Then you can get the area in m2. It's also likely that your textbook has an example of an area or volume conversion problem, which may be useful to look at.

    Hope that helps.
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