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: Express the density of a solid substance varying with temperature

  1. Feb 23, 2006 #1
    I need to show that the density of a solid substance varies with temperature as d = d0(1 - 3aT), where a is the thermal coefficient and T is the change in temperature.

    I know V = V0 (1 + 3aT) and V = m/d. Since m is constant,

    d0 = d(1 + 3aT)
    d0 - d03aT = d + d3aT - d03aT
    d0(1 - 3aT) = d +3aT(d - d0)

    Am I now supposed to assume that the d only changes a little compared to d0, so that (d - d0) = 0?
  2. jcsd
  3. Feb 24, 2006 #2


    User Avatar
    Homework Helper

    do = d(1 + 3aT)
    d = do/(1+3aT) = do(1+3aT)^-1

    now expanding using binomial theorem and as a is very small the higher terms can be neglected, gives

    d = do(1- 3aT + ....)

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook