I hate when that happens. Mine was caused when I decided I might try night school to finish a degree, they gave me credit for a number of calculus courses I’d taken in the past but I hadn’t hadn’t done any in 7-8 years. First night of class guy walks in and says three words: “I am am Tarnowski” He then proceeded to fill the entire chalkboard covering the front of the room with one problem, questions prompted a look as if he couldn’t understand how everyone wasn’t born knowing this stuff. My first thought after picking my jaw up off the floor was WTF am I doing here? The ‘C’ I got in that class may be my greatest academic achievement. But I will never forget those three words, screeching noises on a blackboard are a symphony in comparison 
OK, the friction thing makes sense. It’s a function of weight and coefficient of friction, not surface area and CoF. So the same weight spread over a larger area has the same friction as all the weight piled on the head of a pin (balance notwithstanding). Note I specifically said weight, not mass, since it’s the force applied to the body, not the mass of the body (friction vs inertia).
Yeah, i was a late bloomer. Didn’t go until I was 34, so the calculus I took in high school was long behind me. Turns out I didn’t even understand it back then, lol. I tested into calculus, so I thought I was pretty good, but the second class was an algebra review. Dude gave us 3 exercises to factor in 15 minutes. I made it halfway through the second problem. Talk about embarrassing.
I set a meeting and he agreed to let me drop the class if I could find a precalc prof to let me in. I did those two semesters with no calculator (except for the 2 chapters with trig estimation, where it’s either that or a chart) because I wanted to make sure it never happened again.
By the time I got back to the calc class, I was stupid ready and breezed through with a 100 and a 99 for the courses. I took exams and had so much extra time I’d plug functions into my calculator to test my answers, just so I wouldn’t feel like I wasted money on that thing, lol. I didn’t need it for anything else.
Math made so much sense to me at that point I changed my major.
Yeah, it took me a while but eventually I realized how truly elegantly both math and physics describe so much of our world.
I got sucked in to probability about halfway through. Mostly because I was more concerned about employment than my education. Pretty sure physics and/or engineering would have been more fun. Found out about actuaries and it was all over. I got through the first 3 exams before my first fail, then covid happened and nobody knew how the testing cycle would go so I’m stalled out. That one only comes along twice a year, soooo…
Little did I know I’d end up doing more spreadsheets, vba, and sql than math, but whatever. A paycheck is a paycheck, and if we ever start paying teachers at least I’ll have a retirement option.
I often wonder how I would’ve done in this time. I did a few years of school In the late '60s when so much was just pure tedium, no pocket calculators/ computers, can’t really say I loved it. At least in part because at the time, HS guidance counseling offered neither guidance nor counseling, I got ‘you did good in math on your SATs, you should be an engineer’ with no explanation of what that entailed and nothing asked about my interests. I think in some ways having a little black box to do the grunt work gives you more time to actually understand why the math and physics take you where they do.
Depends way too much on the teacher. I have to check in with my kids on all their math/science classes because their teachers often don’t understand math on a deep level. I can’t even remember the last time Rhett had a math teacher that majored in math. All education majors that passed a math test for the state, where I think they get to use calculators.
At least one of them couldn’t even explain the benefits of learning math.
Oh, I completely agree about the need to learn the mechanics of doing certain functions manually but I also believe once you know how and get involved in things that may require thousands and thousands of those calculations, the little boxes are a good thing and free you to think of other things.
My college has a 5 year program where you get your BS in physics and MS in engineering flavor of your choice. I did that, with a non thesis option and I bolted. It was risky though. I would have ended up with a decent job no matter what, but I managed to get lucky and get a great job writing software for unmanned ground vehicles. Physics on its own is really only good for getting into grad school or proving to a potential employer that you are good enough at learning to learn on the job. I have almost forgotten everything from my higher level physics classes.
You don’t think it gives you a lot of insight as to why things work(or don’t) the way they do?
Physics 1&2 (Newtonian physics) are definitely useful. I use that all the time. Thermodynamics is a higher level course that is very practical too. Physics 3 (relativity) and beyond is only practical on a very grand scale. I’m sure there are effects in wires that require modern physics to explain. But modern physicists have found them already and given us engineers the cliff notes.
Professionals who work in physics have a phd and have done some post doc work and are now physics professors or work in the world’s best labs. That’s what I mean when I say a degree in physics helps you get into grad school.
There are a lot of other people with physics degrees who aren’t doing physics and it is good for that too. I would (usually) prefer to hire someone with a physics degree to do software engineering than someone with a computer science degree. Because making it through physics means you have the problem solving skills needed to work in research and learning to code isn’t very hard by comparison.
Quantum mechanics isn’t valuable to me in any of the problems I am trying to solve. I learned a lot while learning it that was useful, but the actual physics has been dumped (outside of Newtonian and thermo).
I used a variation of this. Everyone in my field seems to be pretty smart, especially the ones doing the interviews. So, saying that I was good enough at learning worked great when I got a job in manufacturing (oddly enough, they thought my car hobby was an important skill, too).
Interviewing for my current job though, I pointed at my GPA, the degree, the full time job I held, and 4 kids my wife and I have…“I kept all this together because of my determination, focus, support, and priority management. I can keep up with this job, and I can deliver for you.”
Gotta sell it if you want it!
As the holder of a Comp Sci degree, and the recent recipient of the news that my contract has been canceled due to COVID-related economics, this does not make me feel good. 
Of course, I think the 30-odd years of experience in IT-related work probably has more to do with hiring decisions than a 25+ year old degree… 
Once you’re 10 years away from college, the degree doesn’t matter anymore. That’s why you have to fight so hard for that first job. Also keep in mind, I work in a bleeding edge research field. So my POV is skewed towards being able to solve a new problem in a short amount of hours. Not applying known experience to common problems (which there are a lot jobs for).
I’m sure you’ll land on your feet K. You’re a smart cookie. There are always more IT jobs. I hope you find something to your liking and I hope you enjoy a short break in between.
I remember our structural engineering teacher showing us why a sky bridge in Kansas City fell down and killed some people.
The engineers had designed multiple threaded rods to support the two-level bridge. The steel threaded rods went from the roof structure down through the second level and all the way down to the underside of the first level of the bridge. IE: the rods were threaded for the entire 24’ length of the rods.
The contractors cut cost and just installed a 12’ rod from the roof down to the underside of the second level and installed another 12’ threaded rod mounted to the top of the second level down to support the 1st level of the bridge.
They did not increase the size of the rods.
By splitting the rods into two 12’ sections they (Doubled) the load on the nuts under the second level walkway. Because the full length 24’ rods were only supporting one floor level at each floor to rod connection.
Now they were essentially forcing the connection below the second level to carry both the second level floor AND the full weight of the first level floor.
Those connections failed and the entire bridge fell to the ground.
From that point forward I vowed never to give “structural” commentary to a client. If we need structural input I tell them they need to hire a structural engineer.
Well, I feel partially responsible for stirring the pot on the PETG discussion but, to be fair, it is mentioned as a potential substitution on MPCNC section of this site. As far as my reasoning, I have found PLA to be rigid but more brittle and, as an ME, absolutely hate brittle failures (and it gets really hot here in Texas). I was willing to sacrifice rigidity for what I viewed as a more durable material and no worries about temps. I didn’t intend to promote something that isn’t ideal. That said, it appears to have led to engineering / physics discussion which is nice.
No worries, discussions can lead to progress. This one always gets me.
This keeps bouncing around in my head and I think I have finally figured out how to easily solve it. Different phrasing.
If changing the print specs could make the part more rigid, it would make it more rigid no matter the material. So no matter what, the more rigid base material will always be more rigid.
As for the brittle part…you will never have a brittle failure on an mpcnc. Again, the differences are not slight. Look up the spec sheets.
Haven’t we seen tabs break off when people put a lot of pressure from screws to hold tubes? Clearly clamping too hard with screws is a problem, but I’m not sure “never” is right there. I would agree that having more rigid parts is preferable, since brittle failures are uncommon and easy to spot (and fix).
Hmmmm, okay. I don’t think I have ever seen a brittle fracture from use, only from over tightening.
More to the point. If someone wants to test printing strategies (infill and perimeters), to see what is better than my recommendations I am game. I think something like the core clamps, or tool mounts area good useful test part.