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Homework Help: Just started physics and need help!

  1. Jan 28, 2005 #1
    I cant figure out how to get the answer with the given info, pleas help.

    In the fall of 2002, a group of scientists at Los Alamos National Laboratory determined that the critical mass of neptunium-237 is about . The critical mass of a fissionable material is the minimum amount that must be brought together to start a chain reaction. Neptunium-237 has a density of .

    What would be the radius of a sphere of neptunium-237 that has a critical mass?
    Express your answer in centimeters to three significant figures.
  2. jcsd
  3. Jan 28, 2005 #2
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