Was just helping my oldest with his AP Chem homework. I haven't taken a Chem class in 28 years.
He was trying to figure out an energy transfer problem where he'd be putting 100C metal into 20C water and trying to find the final temperature of both.
He kept setting up the problem as Tlost=Tgained and just kept beating his head against it (for a day and a half).
I looked it over and his math looked right. I said "bring me the book". He brought me a homework packet... Something looked wrong (a positive that "should" be negative if you do the problem Tlost=Tgained). So I reiterated: "bring me the book."
Looked it over, and there it was...
Tlost = -Tgained
I still don't know sh!t about chemistry, but I know if the math looks right and you're getting a completely impossible answer, you're not setting up the problem right. And the book should show you how to set up the problem. And it did...
And he'd have saved a lot of time if he'd looked closely at it.
So he learned a valuable lesson. RTFM, son.
