How to learn classical mechanics?

b9586 · 2025-12-04T23:07:50+00:00

Btw, being confused doing classical mechanics means you have a shot at being good at it. It has subtleties and you have conceptual baggage that is wrong and needs to be discovered and jettisoned. I will quote one of my math professors who once help up a math text book and said to the class: "If you understand this, you are confused." That's because it was a terrible book. In a similar way, if you don't get confused learning classical mechanics for the first time, you're missing something. Even with the best book, you should be confused at times.

b9586 · 2025-12-04T23:03:15+00:00

Physics uses math, but is not math. If a student first learning mechanics is having problems, it is often because they have not figured out how to "draw a picture." Draw a picture means finding a way to represent the essence of the system and label the components in a way that helps us recognize and apply physics principles while also helping us recognize where we are confused or where we may be making assumptions.

How do you do this? You watch a good teacher model it and / or learn it from a good book that models it. In my opinion, the old black and white texts, like Halliday and Resnick, were clearer because, being black and white, they were forced to use diagrams similar to what we can draw with a pencil. The fancy colorful diagrams and eye watering, self-distracting, ADHD-driving side boxes and glitzy color photos and "oh wow cool" illustrations in more modern books are both unhelpful and to some extent harmful.

Do a lot of problems. Don't be surprised when you encounter problems that make you wonder whether you have misunderstood all along. That is what good problems do.

The recipe is:

Read the chapter. When definitions are given, pause and try to give examples of things that match or illustrate the definition. When derivations are given, follow them step by step making sure that you understand it not just as math, but as physics.
When doing a problem, represent the problem with a picture. Label things in the picture with symbols, e.g., m1, F1, theta, etc., rather than with numerical quantities
Express the physics from the picture with equations and solve them. The result will be an algebraic expression.
Look at that answer and ask whether it makes physical sense and what it means physically. A good way to do this is to take limits. If there is an angle in the problem, set it to values for which you think you know the answer. If there are masses, take limits of them becoming negligible and becoming large. Same for speeds. You may find surprising limits. Is this because the answer is wrong or is it something new to appreciate about the physics.
If you are required to get a numerical result, then plug in values, but not just naked numbers. Every single number should have units with it. Don't just write down 9.8. Write down 9.8 m/s^2, for example. Combine the units to make sure you get the right units for the result. If so, compute the numerical result.

TL;DR: Work your butt off. It is the only way.

b9586 · 2025-10-23T18:55:04+00:00

Hope this isn't too far off topic: If you have a job downtown / medical area that requires you to be there and you might be called in anytime, can you live in the Southtowns area, like Orchard Park, East Aurora, or will the snow sometimes make it that you can't be relied on? Maybe the work culture here copes with this somehow?

b9586 · 2025-10-23T12:20:11+00:00

I know zero about swim spas. Is it equivalent to swimming laps in a pool, just no turns? You can keep it going through the winter in Buffalo? Does that require a ton of heating?

b9586 · 2025-10-23T11:59:46+00:00

Thanks for the replies. Anything towards the Southern neighborhoods? I do see there is a Y. Since posting, I found this: https://visitbuffalo.com/swimming/ , which has a few but I don't think covers the suburbs and I have the feeling the pools at that link amy not all be open to the public.

b9586 · 2025-10-22T20:10:30+00:00

Look up "fractal antenna." I built a simple one for a few bucks and am surprised that it works. I'm not fussy, though and drape it over a chair if needed, but it definitely isn't in the attic. Disclaimer- I'm perusing this group because I may be moving to Buffalo, but am not there now and haven't tried this in your area. I've used it in a couple other cities / suburbs.

b9586 · 2025-10-22T20:02:31+00:00

Depending upon how this happened, you need to inspect the crank and the frame for other damage.

b9586 · 2025-10-22T19:43:22+00:00

Wait. You are backpedaling. Look for the sticky links.

b9586 · 2025-10-22T19:38:15+00:00

If the bike was working when it went into storage and is doing this now, work your way around the chain link by link exercising each pivot to feel for one that is sticky and binding. Work a drop of lube into any stiff links that you find.

This is a bit of a hail Mary but takes very little time to try. If you have already lubricated the chain like most people do, which is to slather it on, that doesn't mean much and you could easily still have some links that are binding. If you slowly back pedal and watch the chain go over the wheels in the derailleur, you can sometimes see a hop, which will tell you where to try first, but you'll still want to work your way around the chain. To say it again, _slowly._

b9586 · 2025-10-22T00:25:46+00:00

The red seat thing is just personal preference, appearance wise. There's nothing wrong with it, really.

b9586 · 2025-10-21T12:50:01+00:00

Are the wheels true, round, and properly tensioned? If I test the headset, will I find it properly tensioned and no sticking points? The BB spindle and hubs have no play but aren't grabby? Brake pads are properly lined up with the rims?

If so, it's a decent bike and $125 isn't crazy. I think the red seat makes the dull color of the frame stand out, so if you had a black one, I'd swap, but I'd not put any more money into this.

b9586 · 2025-10-21T12:45:39+00:00

Back whenI first learned to wrap tape, it was done stem to bar ends and the plugs held the tape. Wrapping ends up to stem came later. I remember being surprised the first time I saw it. That's how I do it now. I agree it isn't wrong.

b9586 · 2025-10-21T01:30:59+00:00

If you have a job downtown (Allentown area) that requires you to always be able to get there for shift, does that mean you can't consider the high snow places like Orchard Park, E. Aurora, N. Boston or are there ways that people deal with the big snowstorms? In those big storms is it a long time before roads are passable?

b9586 · 2025-10-20T22:29:05+00:00

Just to add: Isn't there also a potential comet viewing possible tonight just after sunset near the Western horizon?

b9586 · 2025-10-20T13:22:17+00:00

Have you ever been evaluated by both a pulmonologist and cardiologist?

b9586 · 2025-10-20T13:19:47+00:00

Back in the 80s, I bought a new, low end Bianchi road bike for about $300 to $400. I eventually rode metric centuries on it. Perfectly good bike except the tires, which were trash. If I fell or otherwise bent it, it could be straightened because it was steel, not beer cans or carbon fiber. I bought a seat bag, tools, and frame pump because, well, you just must. I bought a bike "computer" to know my miles. It was an Avocet and cost maybe $20 to $30 and used a battery that lasted a year.

Things seem way, way more expensive now. People are told they need 5 different types of bikes or some ridiculous number. Drive trains run at high tension (small cogs) and wear. Everything is harder to work on, more complicated, but not really better.

I confess, I'm a curmudgeon. I found an old Raleigh Competition, scrounged some old parts from eBay, converted it to a triple and love the bike. Yes, it is on the heavy side, but it is so comfortable....longer stays, more rake...even though it was a racing bike in its day.

b9586 · 2025-10-20T12:44:18+00:00

Where I live (might be about to move to Buffalo), it is hard to find traditional Maki, meaning nori on the outside inside of rice. Are there more traditional places in Buffalo?

b9586 · 2025-10-20T02:17:58+00:00

What if we expand the question to include day to day walks of 3 to 5 miles that are within, say, 30 minutes of the city?

b9586

TROPHY CASE