Notices
Results 1 to 6 of 6

Thread: Wondering if anyone could help me please?

  1. #1 Wondering if anyone could help me please? 
    New Member
    Join Date
    May 2008
    Location
    Henley-on-Thames
    Posts
    2
    Hi, i'm a student and in stuck on a particular science question
    Can anyone help me?
    the question is as follows:

    1. A 1 metre long strut (which is a straight rod) in a pin-jointed frame structure has a rectangular cross-sectional area of 8 sq cms, is subjected to a compressive load of 800 Newtons. If the value of Young's Modulus for the metal is given as 70 Giga-Pascals, find out what decrease in length occurs in the member?

    Answers would be much appreciated :-D
    Thank You


    (: Aiden
    Reply With Quote  
     

  2.  
     

  3. #2  
    Forum Masters Degree bit4bit's Avatar
    Join Date
    Jul 2007
    Posts
    621
    If E is Young's modulus, σ is stress, and s is strain

    σ=Force/area = F/A
    s=change in length/ original length = Δl / l<sub>0</sub>

    E= σ/s = (F/A) / (Δl / l<sub>0</sub>) = F l<sub>0</sub> / A(Δl)

    then

    Δl =Fl<sub>0</sub>/EA

    Then just plug in, and calculate, and watch the units.


    Chance favours the prepared mind.
    Reply With Quote  
     

  4. #3  
    Universal Mind John Galt's Avatar
    Join Date
    Jul 2005
    Posts
    14,168
    Aiden, welcome to the forum. I am assuming this is a homework problem. We discourage giving firect answers to homework. Perhaps if you can tell us how far you have got with the problem so far, what equation you think you might apply, or at least some indication of your thinking, then someone will be more than willing to offer you assistance.

    I see bit4bit beat me to the submit key.
    Reply With Quote  
     

  5. #4  
    New Member
    Join Date
    May 2008
    Location
    Henley-on-Thames
    Posts
    2
    Oh ok...sorry i'm new to this so i didnt know.
    i have been stuck on this question for a while now and it has really started to bother me.

    I really appreciate what bit4bit said because now i know where to start and i reckon i can now eventually work out the answer :-D this isn't my strongest of topics :?

    sorry if i caused any bother
    (: Aiden
    Reply With Quote  
     

  6. #5  
    Forum Masters Degree bit4bit's Avatar
    Join Date
    Jul 2007
    Posts
    621
    My apologies Ophiolite
    Chance favours the prepared mind.
    Reply With Quote  
     

  7. #6  
    Universal Mind John Galt's Avatar
    Join Date
    Jul 2005
    Posts
    14,168
    Quote Originally Posted by aidenlight
    sorry if i caused any bother
    No bother at all. Ask any questions at all, but for homework ones it is always best if you can explain a little what you have already tried. We get some people who come in expecting the answer with no effort. It is clear you are not one of those. So don't fret.
    Reply With Quote  
     

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •