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Homework Help: Need help with this question.

  1. May 8, 2012 #1
    1. The problem statement, all variables and given/known data

    i came across this question while revising, can someone talk me through it please. I need to calculate the dimensional change.

    The stator of an electric motor winding is to be expansion fitted into its housing. if the diameter of the stator at 20 degrees C is 150.1 mm and the diameter of the housing is at 20 degrees C is 150 mm, determine the temperature to which the housing must be raised to facilitate the assemble.

    The coefficient is 12x10 ^-6 degrees

    2. Relevant equations

    ∆L/L = α∆T, α is linear thermal expansion coef
    3. The attempt at a solution
  2. jcsd
  3. May 8, 2012 #2
    You are given L, α and ∆L is something you can calculate (how much stretching do you need?). Then use that equation to solve for ∆T.
  4. May 9, 2012 #3
    do you mind showing me how to do it ? with a different question perhaps? i have just started to learn and im not very good at maths
  5. May 10, 2012 #4


    User Avatar

    Staff: Mentor

    Hi naim! http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif [Broken]

    You provided this equation: ∆L/L = α∆T, α is linear thermal expansion coef
    and you said The coefficient is 12x10 ^-6 degrees

    I think the coefficient of linear expansion should be expressed "per degree", i.e., 12x10 ^-6 /degree
    and you should have been told whether Celcius or Farenheit

    So the first step in to fill in the information you know:
    L =
    ∆L =
    α =
    ∆T =

    If necessary, convert the above to standard units because equations always require that the data be expressed in standard units.

    Next, re-arrange the equation so the unknown quantity is on one side by itself.
    Last edited by a moderator: May 6, 2017
  6. May 10, 2012 #5
    Thanks dude :)
  7. May 13, 2012 #6
    can someone help me with this ?

    Dry steam is compressed isothermally from a pressure of 1 bar to 4 bar. if the initial volume is 0.5 m^3, calculate the volume of the steam after compression
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