# Need help with Heat Flow question

1. Mar 17, 2005

### Gonger

I have a question I'm trying to but I dont really know where to start. It is kind of an add-on to a previous question that I got pretty easliy. This is the first question:

The answer to that was 156000 W. Now the second question asks how much heat must be supplied to raise the temperature and this is what I dont know how to do. This is the second question:

If anybody has any help for me that would be great. Thanks

Last edited: Mar 17, 2005
2. Mar 17, 2005

use your same approach as in question 1. Find out the amount of heat lost in the heating process, and then find out the amount of heat needed to raise the temp the air in that volume. Then use q=mct, and fool around with the equations. You should be able to get it.

Regards,

3. Mar 18, 2005

### Gonger

the thing I dont know how to do is find out how to calculate the heat needed to raise the temperature

4. Mar 18, 2005

use:
$$q = mc \Delta t$$

you need to find out what c is for air, and what the mass of air you have in that volume. For this you need to know the mass per unit volume of air. Once you find these out (data tables), you can solve for q. Then once you hve q, you have the amount of heat needed to rise the temperture, but you need to remember that there is also heat loss through insulation.

Regards,