<p>Hi, I took the AP Physics B this year, and I am taking the SAT II this saturday. I took some practice SATII's but I found difference between SATII and AP.... (even though Collegeboard makes both exams....)
In Thermo, the change in internal energy (delta U) = Q + W, where Work is positive when done on the system, and negative when work done by the system. (IN AP)
But in SAT II (I found that SAT has it the opposite.. where delta U = Q - W, where Work is positive when done by the system and negative when work is done on the system)
Maybe it was just Q - W on some textbooks... Can someone tell me which one to use for the REAL SAT II test?</p>
<p>Same thing.
SAT II uses Q-W however.
SAT just thinks that W done on by the system is positive like you said.
Remember that work is relative to the inertial frame.</p>