:huh:
Well, I took it for the first time also, so I don't exactly have a different frame of reference as you: So I hope that this post can still be helpful.
I also found the PM exam to be more difficult than I expected from the "the other board" sample problems. I spent considerable time studying for the PM portion, since I work in an evironement where the stuff I design is "simplistic" mechanically. I felt weak in deep Machine design. ( I NEVER do any Thermo/HVAC)
I came across a problem that actually had a formula for in in the MERM, but there wasn't enough info for me to complete it without doing some guessing on the procedure. My take on this is that "the other board" tries to cover all bases, but can't really predict how bizzarre the obscure stuff can be framed in the PE exam.
(I can't discuss the actual question)...
Don't beat yourself up: I felt sooooo strong after the AM portion, but the PM portion knocked me down! I don't think that very many people will do well on it, regardless of their level of preparedness.
So, you/I could pass, it could happen!