Discussion of Lever Launch Results
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- Опубликовано: 27 авг 2024
- I've finally finished the lever launcher experiment, and over 26 different trials covering 13 different physical setups, the data shows that angular momentum is conserved to a high accuracy in the collisions and that you do not get free energy out of the experiment .
While I'm hoping that the video does a good job of covering the methods used in both the experiment and the analysis, I wanted an opportunity to address questions that people might have about the experiment, and after that maybe have some free form discussion about ideas in physics/scientific critical thinking/etc.
Michael, thank you for all your hard work. The costs and time you put in to preparing and doing the experiments went above and beyond. You won't appease DS or shift his thinking. He's cornered himself into never being able to admit error, which must be a horrible thing to live with. But, buy the ticket take the ride, and all that.
The invective in his response means you're over the target. It's called narcissistic rage, which happens when a narcissist's beliefs about their perceived importance or grandiosity are publicly undermined. It isn't a you problem, it's a him problem.
All that aside your videos are worth their weight in gold. I'm learning a lot from you. Billy Connolly was once asked to explain something he gets a kick out of. He said he enjoys watching people who are skilled at what they do. Same here. Cheers.
Blocking draft science was a wise move. He's already done a hysterical response video where he's screaming and raging about bringing Physicist Michael down. This is not the conduct of someone serious about scientific inquiry.
Ah, I thought you were on about me!
I said I did that in a previous comment.
I see that _Michael_ 👼 is taking note
of our objections to "him". 😁
Anyway, I think a temporary block
from _Michael_ 👼 would suffice
to get the _message_ through to
🦁👱👺🤬.
Just enough blocking to iron out any issues, then finish all this off with a _coup de grâce._
@@The_Green_Man_OAP Why would you think I were on about you? Honestly, I'm not entirely sure what you are talking about (no offence intended).
@@glowing571It's either _my MASSIVE ego_ or the fact that I posted a comment saying _I'm blocking DS_
(or words to that effect) in a previous video on this channel. Anyway, one of those thumbs is mine 👍.
Just thought of an alternative DS emoji: 👨🌾
- Feel free to guess what that is.
@@The_Green_Man_OAP Hmmm....is there an emoji for someone having a rage-stroke? 😁
The Saga ends for now... For a good while (5-6 years ago) Draft was convinced he was going to win a nobel prize in physics. I think he finally gave up on that. 🙄 Anytime you mention nobel prize winners he gets into rage mode.
omg dog!
I've got no problems with the Physics you use (yet - I'll need to go over the video a few times and think about it).
But there seems to be an mathematical issue with error handling (% difference between measurement of motion and prediction of it, mentioned at about 30:29 ) which I mentioned before.
I'm not sure yet if this can be declared as one dimensional motion, because the lever is rotating on a plane.
Imho, its best to check if the measured and predicted vectors coincide or not in the same place at the same time. Time error might mean that the vectors do not coincide.
I think this is worth pursuing because if the maths is right you could do better than just a range of values, and maybe get the error down to 10% or less in any case, which would be more reasonable.
35:30 The only thing to consider there is the slight difference in mass distribution, as long as you don't put it on the bumper that is part of a collision, obviously... If it's near the centre of mass, the difference between the dynamics of each mass should be negligible.
40:26 Awww...🐩 🥰
41:14 To the Flearthers:
1. _Buoyancy_ requires _gravity._ 🍎⤵️
2. _Earth is round_ 🌎
To Michael:
1. _Body_ and _surface_ forces. 🏋️🏄
2. _Force density._ 🔪🗜️
3. _Pressure gradient._ 💦🌐
- _What are they?_
I've noticed that the side chat doesn't show when I replay the video.
Last time I did one of these it took a few days before the chat replay showed up.
@@PhysicistMichael 👍
Ah, yes, I see the chat is up now. Thanks.
I apologize for not entering my question when you asked for it, but I'm not at my usual PC, but I'm using my notebook at the moment, and I can barely read my own comments since the sreen is so small, and in addition, some keys don't work properly because I accidentally dripped some coffee on my keyboard after I soacked my cookie in my coffee a while ago, topping this all off with the fact that I'm not a native English speaker.
But the question I had was about the energy that remains inside the lever after it is no longer pushing any of the carts.
Can we not use the velocity of the cart that was pushed last, and then calculate the speed of the tip of the rod from it, and divide that by two, to find the energy left in the lever with ½mv²?
I too have had enough of the lever by now, so I think we may conclude that, ignoring the losses, we can say that for the conservation of angular momentum goes: m1v1 × r1 = r2 × m2v2 or: p1 × r1 = r2 × p2.
It would be nice to have some future experiments about the inelastic collision, but on a linear track of course.
I wonder if there is any difference in using velcro or small magnets to make the carts connect when they collide, but I think the extra effects of the magnets cancel out, since they are in opposite direction.
I want to tell everyone about the persistent misunderstanding, that for the inelastic collision goes that the kinetic energy must be conserved, but for some undefined reason, half or so of the energy will disappear into thin air.
But that is a strawman, nobody ever made that claim, energy cannot be created, nor can it be destroyed.
Somewhere in history people asked an authority where the energy goes, when we compare the elastic collision with the inelastic collision.
But the authority had no clue, and afraid of falling from their pedestal, they answered that the energy simply disappeared, yes disappeared... eh... disappeared into... eh... heat, yes heat, that must be it, the energy simply disappeared into heat, just like everything always disappears into heat.
And so this unfounded emergency brake became the persistent explanation for the non conservation of kinetic energy in the inelastic collision, parroted by all physicists till the end of time.
Now please take a look at the pendulum for a second.
The kinetic energy of the bob at the lowest point is converted into the potential energy at the highest point of the bob.
½mv² = mgh
Does anyone claim that the kinetic energy is conserved here?
Well no, of course not.
The 'energy' is conserved, not the 'kinetic' energy.
The kinetic energy is transformed into 'work', and this work made the bob go up against gravity.
I guess the inelastic collision needs something similar to that.
The elastic kinetic energy of the cart after the collision, must be transformed into inelastic work to make the velocity zero first, and then the cart needs to be accelerated into the opposite direction, until it reaches the final velocity of the two connected carts.
Rememer that the other cart has to be accelerated to this final velocity too.
All this 'work' has to come from somewhere, so it has to come from the initial kinetic energy.
Make no mistake, the energy is conserved, also in case of an inelastic collision.
Initial kinetic energy equals work done plus final kinetic energy.
The missing energy disappears into... work done.
The conservation of kinetic energy in the case of the elastic collision should therefore be considered a 'special' case.
However, changing the direction of a moving object, should not be considered as not doing any work.
And therefore we should try to understand that work can certainly have a direction.
And when work has a direction, so has kinetic energy.
Thanks Michael. 👍
@@PhysicistMichael Yes, I was expecting Goofy to be blocked at one point.
Goofy mentioned in their videos once or twice that they were blocked from debate groups after they warned Goofy to substantiate their claims and stay on the subject.
When Goofy ignored the warning, they were blocked.
Goofy is blocked everywhere.
Take care.
@@_John_Sean_Walker That was the Naked Scientists forum. DS stole their code and posted exact copies of the forum on his site.
*But the question I had was about the energy that remains inside the lever after it is no longer pushing any of the carts.
Can we not use the velocity of the cart that was pushed last, and then calculate the speed of the tip of the rod from it, and divide that by two, to find the energy left in the lever with ½mv²?*
That would be assuming the very thing we want to prove. If we're trying to test conservation of energy, we need to have some alternative method to calculate how much energy each piece of the system has. There are other ways that energy can be lost.
*But the authority had no clue*
I think this is a bit unfair. There are lots of inelastic collisions where we can demonstrate that some of the energy is transferred to heat. If I give an object a push and then it slides across the ground, that's a collision (interaction) between the object and the Earth, and as an object slides across a rough surface, it heats up. The amount of thermal energy added to the system matches the work done by friction.
When you talk about the work done by a force, that is the amount of energy that force either adds to or removes from a system as it goes through a displacement. If you have a conservative force (like gravity, spring forces, etc.) the energy that is removed (or added) can be associated with an increase (or decrease) in a potential energy associated with those forces. For non-conservative forces (friction, air resistance, etc.) there is no associated potential energy, so the work done by those forces will end up as some type of non-mechanical energy, such as thermal energy.
I agree that inelastic collisions don't _necessarily_ have their energies end in thermal energy. Consider a collision between two carts using a perfect spring, we'd get an elastic collision. But if we have a ratchet connected to the spring, such that it won't expand after it is compressed, we'd have an inelastic collision (KE not conserved) but that lost KE is just being stored in the spring, so we could get it back later (releasing the ratchet). When object hit, some of there energy would be lost to vibrations, or sound waves, but those often dissipate into heat in fairly short order. I could imagine a collision where some chemicals are placed between the colliding objects, and the KE transferred to the chemicals during the collision enables a reaction and some of that energy is transferred to new chemical bonds.
So, while I do agree that the KE lost is due to work done, that's the case for any change in KE, and for most inelastic collision cases a very significant portion of the energy will be converted to forms that quickly end up as thermal energy.
*However, changing the direction of a moving object, should not be considered as not doing any work*
Work done is a scalar quantity by definition (W = dot product between force vector and displacement vector, and the dot product produces a scalar). If I apply a force on an object in a direction perpendicular to the direction the object is moving in, the direction that the object is moving will change, but using this definition, that force will have done no work.
These last two paragraphs are missing important points about the internal forces that would be acting on the objects during the collision. Take the carts colliding with the spring in an elastic collision. During the collision itself, the total KE is not conserved, because when the spring is partially compressed, some of that KE has been momentarily converted to PEspring. Even without a spring, there are lots of internal forces that would be acting between and inside of the colliding object (down to intermolecular forces in any deforming solids). As the object deforms, all these tiny forces would be doing work on the system. If those forces don't pass their elastic limit, we might easily get that energy back as the object returns to its original state. If it's past the elastic limit, not so much.