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!

Homework Help: Please explain Young's modulus

  1. Jan 16, 2010 #1
    1. The problem statement, all variables and given/known data

    A 0.46 m long guitar string, of cross-sectional area 1.1 10-6 m2, has Young's modulus Y = 2.20 109 N/m2. By how much must you stretch the string to obtain a tension of 10 N?

    2. Relevant equations

    ???

    3. The attempt at a solution

    I don't know how to begin this problem. What is Young's modulus, and how is it used?
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Jan 16, 2010 #2
    youngs modulus is the ratio of stress to strain

    stress is given in force/unit area

    strain change in dimension/original dimension (no units)

    all values are given except change in dimension
     
  4. Jan 16, 2010 #3
    so do I use hooks law?

    F/A=Y delta L/L

    I got it! The answer is 1.9 mm.

    Thanks!
     
    Last edited: Jan 16, 2010
  5. Jan 16, 2010 #4
    Yep. That's using the definition of Young's Modulus!

    Isolate your unknown variable, [tex]\Delta \ell[/tex] as a function of all your known variables, [tex]F, A, \ell, Y[/tex] and just stick all the values into the formula you get.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook