You've had a great prof! Mine unfortunately wasn't as good and just handed me the book and asked how much energy it would take to lift it. Myself, thinking of muscles as linear motors rather than solid structures, said something along the lines of: "Depends on how fast you want me to do it. Just holding it I have to exert something like 10 watts, give or take", and he went absolutely wild, calling me names and saying that I'm dumb for even asking it, implying that it takes no energy to hold things, hence the plank challenge. Gotta admit, though, that I might have missed the topic of that particular lecture as I wasn't paying as much attention to it as I was about writing everything down with perfect formatting in LaTeX, hoping to catch up before the exams... Which got me in trouble with another prof who denied me from even taking the exam because she thought I was playing games during her lectures (I was the only student who brought a laptop), and to get to her I had to deal with a yet another prof who thought I was an outlaw biker because she saw me wearing a leather jacket, and tried to humiliate me in front of the board. Still a step up from a different uni that had the audacity to post a price-list for the grades on the door to exam room... One is the top university in my home region and second is mid-tier in the capital, so this is basically the sad state of academia in Russia, and, by certain extent, CIS countries. Speaking of which, do you happen to know any good (and preferably free) online courses on maths and physics? I know about khan academy, but it's a bit hard for me to chew through, and 3blue1brown who's been absolutely invaluable in clearing some of the crucial concepts I needed both for work and for learning stuff in general. Even though I'm fairly well off without it, I'd like to someday figure out what's the deal with quantum computing is, and not just that "a qubit is both 1 and 0 at the same time" which doesn't seem to make much sense to me.