IM NOT A TEACHER
IM NOT A TEACHER!
Ahhh, Ive just done an essay on something like this for stylistics. The second one is breaking the Gricean maxim of quantity forcing the hearer to determine the implicature in what the speaker is saying (which is what he thought of the physics lesson). They are both the same only if the hearer understands the implicature. If the hearer didn't understand then they would simply reply 'about what?'
I hope this helps, but I'm not a teacher!