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: Need help related to heat, water and aluminium

  1. Oct 11, 2012 #1
    1. The problem statement, all variables and given/known data
    I need help at identifying what forumala's to use to calculate the following

    (Density of Aluminium 2770kg/m^3
    An aluminium plate has a mass of 5kg and a surface area of 2m^2. The temperature of the plate is 450°C. The plate is immersed in a container of water of which the temperature rises from 20°C to 80°C. Only 70% of the heat energy given off by the plate is transferred to the water
    - Decrease in surface area of plate after being immersed in water
    - percentage change in area due to temperature change
    - heat transferred to water
    - mass of the water

    I have been going through the examples in the book and i just don't see how I will work it out. It seems I need a coefficient of linear expansion and coefficient of area expansion
    but I just get 0 both times.

    need to be pointed in the right direction to solve the problem as in formulas that would need to be used.

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Oct 11, 2012 #2


    User Avatar
    Science Advisor
    Homework Helper

    Hi Sl1ver! :smile:
    mmm :confused:

    show us your full calculations, and then we'll see what went wrong, and we'll know how to help! :smile:
  4. Oct 11, 2012 #3
    coefficient of area = A1 -A2/A1(t2-t1)

    and coefficient of linear expansion
    using a as i cant find the proper symbol

    2a = B
    and then end up with zero as well.

    so I cant see how zero and zero will help me
  5. Oct 11, 2012 #4


    User Avatar
    Science Advisor
    Homework Helper

    ah, yes …

    i think you'll need to look those up in a table :smile:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook