Why Am I Struggling with Thermal Physics Calculations?

[Confuzzled_VN]

Hi..i was trying out some calculations i found on some site as practice for my exam this Friday and realized that i don't understand at all..
Everytime i tried something..my answers were wrong..

E.i

1. How much heat energy is needed to heat 4 kg of aluminium by 8 (degrees)C?

The answer:

1. Energy = mC(delta)θ = 4 x 1200 x 8 = 38400 J

I don't understand where the 1200 came from..

Can anybody give me links to thermal physics and general physics notes and/or worked examples for me to try out?

 

[Astronuc]

It would help if one would write units with the numbers in a problem.


Energy = mC(delta)θ, where m is the mass (in this case 4 kg), C is specific heat (which is unique or specific to a material which would be in units of J/kg-K), and θ would be the temperature (in K or °C, and not to be confuse with an angle). Some people use T for temperature.


Here is a good site for some basic physics - http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

and for the problem at hand - http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/spht.html

Table of specific heats - http://hyperphysics.phy-astr.gsu.edu/hbase/tables/sphtt.html#c1
C_p = 900 J/kg-K for Al in this table.


Please expend some effort and review the notes on Hyperphysics.

Thank you.