Oddly, the distance that seems to work well for long lever matches root 12 which matches the moment of inertia of a spinning rod *spinning from its end*. So it's as if we're matching the moment of inertia of just one side of the rod. That doesn't sit right with me though. Hmmm. The sponsor is Odoo: click here to try it for free https://www.odoo.com/r/aykZ

"Lever comment"

After watching the video, now i understand levers less

so i guess you convinced me that i didn’t understand levers from the start

There is such an urge to treat dynamic systems as purely a series of still frames. This beautifully shows the danger in that.

1:06 "I'm sure you'll LEVER comment.."

Good old Steve explains something, I go "aah yes, makes sense" and then he's like "yeah, but that's absolutely not how it works"

This video reminds me of the famous quote: “Aristotle said a bunch of stuff that was wrong. Galileo and Newton fixed things up. Then Einstein broke everything again. Now, we’ve basically got it all worked out, except for small stuff, big stuff, hot stuff, cold stuff, fast stuff, heavy stuff, dark stuff, turbulence, and the concept of time”.

You may want to look up the term "reflected inertia". It explains why the inertia does not scale linearly with mechanical advantage, but quadratically. And actually, it can be generalized to reflected impedance, as all mechanical impedance scales quadratically with mechanical advantage. So this includes stiffness and damping. This is very important in gearboxes for instance. Also, the same principle has been used in theater equipment that makes you fly over the podium, to counteract gravity without adding much inertia.

This seems like the innocuous sounding pre-condition that we got in high school about pulleys ("so long as the system isn't accelerating", the teacher would mutter from under his breath)...

So, as a civil engineering student (25 years ago), I took a lot of semesters of statics and dynamics and so on in uni. Apparently I remembered enough of them to scoff at your "black box" step and mutter "surely the inertia moments of the two systems is different so they behave differently in a dynamic system", but other than that I almost followed your logic as well. I think the intuition fail when discussing levers (and pulleys and inclined planes...) is that the way we're taught about them (at around 10-12 years old in most countries, I believe) is always in a static setup, and the intuition that's drilled into our brains is about their behaviour at equilibrium so we're always reaching for that intuition before thinking about conservation of energy. Not sure what a good framing would be to help shift the viewer intuition that dynamic problems behave differently than static ones. In uni I've been taught the virtual work principle to analyze dynamical equilibrium, not sure what a good explanation would look like.

Unrelated, at some point you touch about how we perceive forces in a somewhat indirect way: I'd point out that 1kg feels WAY heavier if you hold it at an arms length so the brain is doing some sort of proxy measurement there to estimate the force (my engineer's brain would reach for the virtual work concept again, but maybe it's wrong).

11:50 "My sponsor is great, you could even start a scam business with them" 😂

I understand levers.  Once I asked my father what this thing was and where wanted me to put it.  He said it was a leeverite.  I asked him what's a leeverite.  He said, Leeeverite there.

9:41 this reminds me of something from class. We were talking about pendulums, and the weight at the end had no effect on the time to swing back and forth. Only the length of the string.
I think the same principle is happening here.

You're so close to discovering gears and gear ratios. If you rotate multiple levers of the same length around the center and connect them together, you get a gear.

Levers are tricky because they convince us to think about rotational situations in translational terms.  We can get away with that when the small angle approximation applies, but levers tempt us to extrapolate the approximation beyond its reasonable limits.

I love the fact that you have the humility to admit you don't fully understand something and reach out to someone else to help out, and you put it on YouTube.

13:18 whoa clean shaven jump scare

When you said that the experiences were the same that immediately felt wrong to me. I've worked construction a decent amount and I knew instinctually that was wrong somehow. But I couldn't figure out why. This was such a cool video. I love how you take intuition and convert it into understanding.

This topic comes up a lot in tennis rackets. There's a measurement called "swing weight" (unit is kg/m^2). It represents how hard it is to accelerate (swing)  a racket rather than how hard to hold it still horizontally. Two rackets can have the same weight and balance point but different swing weights. The one with smaller mass near the tip will be harder to accelerate than the one with larger mass near the handle despite "mass x distance" being the same.

The concept is "moment of inertia" which determines the angular acceleration of a system.