1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

What is the elastic modulus of the wire?

  1. Apr 14, 2009 #1
    1. The problem statement, all variables and given/known data
    A wire of diameter 0.2mm stretches by 0.20% when a 6.28-N force is applied. What is the elastic modulus of the wire?


    2. Relevant equations
    Elastic Modulus=F/A/L/[tex]\Delta[/tex]L


    3. The attempt at a solution
    r=.1mm=1x10-4m

    6.28N/(2[tex]\pi[/tex]1x10-8/.02=5x109N/m2

    The right answer is 1.0x1011.

    What am I doing wrong?
     
  2. jcsd
  3. Apr 14, 2009 #2

    Doc Al

    User Avatar

    Staff: Mentor

    That should be (F/A)/(ΔL/L).
     
  4. Apr 14, 2009 #3
    Oh, yeah. Well how do I calculate that? I know that the change is .2% if I use .002 or .2 as a value for [tex]\Delta[/tex]L/L I don't get the right answer. What is wrong with my calculation?
     
  5. Apr 14, 2009 #4

    Doc Al

    User Avatar

    Staff: Mentor

    Area = pi*r². Looks like you have an extra factor of two in there. And ΔL/L = 0.002.
     
  6. Apr 14, 2009 #5
    Ah! Thank you so much! I don't know why I was thinking are was 2*pi*r^2. Thanks a lot!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: What is the elastic modulus of the wire?
  1. Modulus of elasticity (Replies: 2)

Loading...