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Homework Help: Young's modulus of a hanging wire

  1. Feb 13, 2015 #1
    1. The problem statement, all variables and given/known data
    A hanging wire made of an alloy of titanium with diameter 0.5cm is initially 6m long. When a 60kg mass is hung from it, the wire stretches an amount 1.44cm. A mole of titanium has a mass of 48g, and its density is 4.54g[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmmi10/alpha/144/char3D.pngcm3. [Broken]

    Based on these experimental measurements, what is Young's modulus for this alloy of titanium?


    As you've done before, from the mass of one mole and the density you can find the length of the interatomic bond (diameter of one atom). This is 2.60×10-10m for titanium. The micro quantity ks[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmmi10/alpha/100/char3B.pngi [Broken] (the stiffness of one interatomic bond) can be related to the macro property Y. Determine the interatomic spring stiffness:

    ks[PLAIN]https://s3.lite.msu.edu/adm/jsMath/fonts/cmmi10/alpha/100/char3B.pngi [Broken]=

    2. Relevant equations

    Y=(FT/A) / (ΔL/L)

    3. The attempt at a solution

    Stress = (60)(9.8)/.1963
    Y= (588/.1963) / (600/1.44)

    I thought everything was set up right.. Need assistance on part 2 also, thanks.
    Last edited by a moderator: May 7, 2017
  2. jcsd
  3. Feb 13, 2015 #2
    Watch those units. Also, arithmetic error.

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