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General physics help

  1. Feb 4, 2009 #1
    1. Consider a commemorative quarter-dollar advertised for sale at $4.98. It has a diameter of 24.8 mm, a thickness of 1.78 mm, and is completely covered with a layer of pure gold 0.215 µm thick. The volume of the plating is equal to the thickness of the layer times the area to which it is applied. The patterns on the faces of the coin and the grooves on its edge have a negligible effect on its area. Assume the price of gold is $10.0 per gram. Find the cost of the gold added to the coin.

    i'm new at this. sorry if not posted correctly

    2. Relevant equations

    3. the area = (3.14)(12.4)(12.4)= 482.81
    the volume = (.215)(482.81)= 103.80
    i know i have to find how many grams there are now, but that's where I'm lost. Do i divide the volume by 10.0?
    Last edited: Feb 5, 2009
  2. jcsd
  3. Feb 4, 2009 #2


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    Homework Helper

    You are supposed to make some attempt before you get help?
    How about finding the surface area of the coin? You could start with one face.
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