Need help related to heat, water and aluminium

[Sl1ver]

Homework Statement

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
Calculate
- 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.

Homework Equations

The Attempt at a Solution

 

[tiny-tim]

Hi Sl1ver!

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.

mmm

show us your full calculations, and then we'll see what went wrong, and we'll know how to help! ​

 

[Sl1ver]

coefficient of area = A1 -A2/A1(t2-t1)
=2m^2-2m^2/2m^2(80°C-20°)
=0/120
=0

and coefficient of linear expansion
using a as i can't find the proper symbol

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

so I can't see how zero and zero will help me

 

[tiny-tim]

It seems I need a coefficient of linear expansion and coefficient of area expansion

ah, yes …

i think you'll need to look those up in a table