- #1

- 98

- 0

## Main Question or Discussion Point

**coffee and milk :) (cooling/heating problem)**

Ok, this is supposed to be easy, but i'm just not seeing it. I've done some heating/cooling problems w/no issue, so i'm not sure why I can't do this one. My teacher posted this quickly at the end of class, and neglected to go over it next class, so I have no one to help me now since no one in the class seems to have bothered with it.

Two cups of coffee (each 150g) at 90 degrees celsius. Cup A has 50g of 15 degree milk added and then sits for 5 minutes. Cup B sits for 5 minutes, then has 50g of 15 degree milk added. Which cup, A or B, is hotter after 5 minutes? Take coffee and milk to both have specific heat of 1.

All I got is that cup A's starting temp T(0)a = [150(90) + 15(50) ]/ 200 = 71.25 degrees celsius. I'm not sure how to set up the equations for this, though. Do I have enough info, or is this guy mad? (j/k, I know it's me.)

thx. :)

Angela.