this post was submitted on 28 Jun 2024
1705 points (98.2% liked)
People Twitter
5234 readers
492 users here now
People tweeting stuff. We allow tweets from anyone.
RULES:
- Mark NSFW content.
- No doxxing people.
- Must be a tweet or similar
- No bullying or international politcs
- Be excellent to each other.
founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
The first two paragraphs are definitely wild, but I guess you've sorta nerd sniped me with the third paragraph.
It sounds like the professor was talking about the concept of work, in a physics sense. In this sense, work being done on an object is effectively just the difference in energy of that object between a start and end point. When you lift an object, it gains gravitational potential energy due to being higher up (it has farther to fall). If you lift it by the same amount, the amount of energy it gains is the same regardless of whether you do it quickly, slowly, or walk around the room and end up back in the same spot. The end result for the object is the same, so the amount of work done on it is considered to be the same. Obviously, in a common sense, some require more exertion than others--that's just not part of what's considered to be work on the object in that sense.
My physics professor discussed the difference between "work" in the physics sense and "work" in the common sense. As best I can recall (it's been years now), his demonstration was basically that he held something out at arm's length and said something like "it's not moving and not gaining any or losing any potential energy, so as far as physics is concerned, no work is being done on it. But the muscles in my arm certainly don't feel that way!" In both cases, you're actively exerting a force to counter the force of gravity, with the end result being that the object doesn't move, and so its energy stays the same. Thus, no work is done on that object as far as physics is concerned.
~~I'm not sure this extends to planking, though--your body is the object, in that case, and you're expending chemical energy to maintain that position. It's all a matter of what you include in the analysis, I guess.~~ Reading up on it, the concept of work in physics only seems to be concerned with forces and motion; I guess that makes sense, since it is physics. With that in mind, I guess planking would also be considered doing 0 work (again, in a physics sense).
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.
I was lucky to have very good professors through most of university (in the US). It makes a huge difference in the experience. I'm sorry you had to deal with all of that, it sounds frustrating as can be. Teachers at any level should be encouraging and helpful, never condescending. I've heard plenty of stories about professors that pretty much power trip over it and use it as a chance to talk down to others, though. It sounds like you've got a lot of them in your area!
Unfortunately I'm not really familiar with the online education space. Khan Academy was what came to mind for me, but mostly only because I've heard it mentioned by others quite a bit. I don't have any personal experience with it or any other sites, so I can't really recommend any specific one to you. I wish you the best of luck in your future education endeavors, though!
I'm also not really any more familiar with quantum computers than you are either. I do remember quantum mechanics being discussed a tiny bit in university, but it was never a focus in any of my classes. It wasn't quantum computers specifically but I recall it being rather focused on statistics; the most specific thing I can remember being probability plots of where a particle might be at any given time (including the possibility that it might tunnel through its container). I never quite grasped it myself, either, but it was never an important part of my coursework so I never really had to.