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!

Change in length (young)

  1. Apr 20, 2013 #1
    1. The problem statement, all variables and given/known data

    A marble column with cross sectional area of 45cm^2 supports a load of 8.5 x 10^4 Newtons.
    The marble has a Young's modulus of 5.5 x 10^10 N/m^2 and a compressive strength of 1.8 x 10^8 Pa. If the column is 2.75m high, what is the change in length of the column?

    2. Relevant equations
    Y(ΔL/L) = F/A

    Where Y is young modulus.
    3. The attempt at a solution

    Y(ΔL/L) = F/A
    Solve the equation for ΔL and you get.
    ΔL = (FL)/ (AY)
    So plugging in the values you get.
    ΔL = ((8.5 x 10^4 N)(2.75m)) / ((.45m^2)(5.5 x 10^10 N/m^2))
    So ΔL = 9.44 x 10^-6
    Can someone double check me? I don't understand why my instructor gave me this number
    1.8 x 10^8 Pa.
    Please confirm or deny my answer. Thanks very much.
  2. jcsd
  3. Apr 20, 2013 #2


    User Avatar
    2017 Award

    Staff: Mentor

    45cm^2 is not .45m^2.
    Maybe to check if the column breaks down.
  4. Apr 20, 2013 #3
    OK. So with that correction

    ΔL = ((8.5 x 10^4 N)(2.75m)) / ((0.0045 m^2)(5.5 x 10^10 N/m^2))
    So ΔL = 9.44 x 10^-4

    Is this correct now? Thanks for the help.
  5. Apr 20, 2013 #4


    User Avatar
    2017 Award

    Staff: Mentor

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Discussions: Change in length (young)
  1. Change in span length (Replies: 1)