This is where the professor’s concept fails. Do they think the linear motion of the one kilogram will slow down as the radius increases? Why do they think it would do that? Have you ever seen and experiment where that occurs?
Your going to have to be a lot more specific than that. In broli's experiment he was checking to see what would happen if you transfere the "vital force" of one mass to another. Would momentum transfere or would energy? Energy did of course. If you were just increasing the radius of a single mass then no it's velocity would not change.
What happens if the one kilogram moving only 3.16 m/sec runs into the 9 kilograms at rest? What happens to the 10 units of momentum we just had? Do we magically believe that Newtonian physics is now false? What happened to Newton’s Three Laws of Motion (they just got violated), where is the ten units of momentum?
What does negating Newtons laws have to do with how energy is transfered? In order to understand where you are going with this let me ask you the same question;
1. What happens if the one kilogram moving only 3.16 m/sec runs into the 9 kilograms at rest?
What do you think will happen?
meChANical Man.
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"All things move according to the whims of the great magnet"; Hunter S. Thompson.
I know what will happen. The one kilogram moving 3.16 m/sec will have only 3.16 units of momentum to share with the 9 kilograms. That means your final velocity will be only .316 m/sec instead of the original one m/sec.
Michael quote: Would momentum transfere or would energy? Energy did of course.
Pequaide: Really since when? Show me one experiment where this has occurred before, other than in the Alice in Wonderland world of WM2D.
Michael quote: If you were just increasing the radius of a single mass then no it's velocity would not change.
Oh: so you think WM2D is programmed to conserve energy not angular momentum.
Broli: Could you please place this in WM2D?
Let a one kilogram puck moving 1m/sec, on the end of a 1 meter string; wrap itself around a 31.83 mm (diameter) post in the center of a frictionless plane. This would mean that the string length (radius) would be reduces 100 mm for every rotation of the puck.
Let WM2D tell you the linear velocity of the puck for each rotation. That would be a radius of 1.0 m, .9 m, ….. .2 m, .1 m as the puck wraps around the post. Thanks
Broli .. can you put up a screen shot of your earlier post so that others can see the setup as you envisioned it ? It might be useful to avoid experimental setup errors or arguments about interpretation, especially when dealing with sensitive issues - if pequiade is correct & WM doesn't show the same result as he defines it, then we need to investigate further, perhaps different sims done in different ways etc - should be able to get to the bottom of it with co-operation from everyone - just an idea :)
Michael wrote:That's because coe is based in reality. You can check these facts, a physicist will often say first year physic students often confuse momentum with energy.
I suppose 'reality' is what you make it. So if you choose to bury you head in the sand, that is your own personal reality.
As a programmer, I can understand the predicament the WM2D programmer would have been in. The equations for conservation of momentum (p=mv) and conservation of kinetic energy (E=0.5MV^2) are mutually exclusive (except for when V=0 or 1 or -1). Because V does not normally equal V squared.
So faced with the practical problem of writing some code - what to do? The one thing that physicists are 'most sure of' is their hallowed COE. So if in doubt, do not blaspheme the sacred text.
But the sacred text of COE has dubious beginnings, and some embarrasing paradoxes. Fortunately, the concept of 'Energy' can hide behind the notion of differing quality levels of Energy. So when 1 + 1 fails to equal 2, we can invoke various levels of obfuscation to make the problem go away.
Very few people are brave enough to admit that they can see the Emperor's Johnson.
Before anyone corrects me - oops - there is no such law as the "Law of Conservation of Kinetic Energy". And yet because of the doctrine of COE, we have to try to make kinetic energy appear to be conserved. I am indebted to Pequaide for pointing out situations where COM & COE are in conflict. I understand the reasoning that unaccounted energy loss can be explained as heat, and noise & stress, etc.
But what is the reality of real world experiments? That is all that counts. No amount of armchair pontification can resolve this.
I will clean up the experiment and post the file and a video. I also forgot to mention that WM2D violates conservation of angular momentum as the total goes down too when the radius increases.
Jake; you set up an elastic collision; I set up an inelastic collision. Did you have a computer answer? What if you swung the 1 kg around and headed it in the same direction as the 9 kg? You would get 8.216 units of momentum.
In an inelastic collision when a 1 kg object moving 10 m/sec collides with a 9 kilogram object at rest the combination will move away at 1 m/sec. The thought experiment being discussed is obviously the reverse of this, yet WM2D predicts a different outcome. WM2D gives you a 1 kg object moving only 3.16 m/sec.
This simulation shows how wm2d does not respect the conservation of momentum (both linear and angular). Instead it violates them in order for the conservation of energy to hold. This is a very evil act as about 70% of the initial momentum in the system has completely disappeared without any excuse.
pequaide wrote:Could you please place this in WM2D?
Let a one kilogram puck moving 1m/sec, on the end of a 1 meter string; wrap itself around a 31.83 mm (diameter) post in the center of a frictionless plane. This would mean that the string length (radius) would be reduces 100 mm for every rotation of the puck.
Let WM2D tell you the linear velocity of the puck for each rotation. That would be a radius of 1.0 m, .9 m, ….. .2 m, .1 m as the puck wraps around the post. Thanks
That experiment is a bit tricky. It's not as straightforward as letting the radius increase as that would happen on its own if the weight is fixed to a a rail on the wheel.
Where as a weight wraps around a pole this will create a force with two components; one component will be radially inwards decreasing the radius of the mass the other component will be tangential decreasing the speed of the mass. So instantly conservation of momentum is gone. I have to think of what this exactly means. Because according to newton's third law the reaction force must do work on the other mass (the pole), since the poll is stuck to the earth this means the earth will have the reaction torque and thus the energy will be transferred to it.
I added the same weights on the opposite side to make it completely symmetrical. Now the wheel won't need to be pined down anymore to the background (aka earth). The whole setup is suspended in space so there's no question about mysterious background forces. WM2D CLEARLY violates conservation of momentum. Someone should have a talk with their developers.
Pequaide let me be clear so there is no misunderstanding. If you had 2 objects of different masses, and each had a different velocity, and
1.they were to interact until equilibrium,
the exchange that happens between both when they interact with each other would of course depend upon the setup; the rates of momentum might oscillate back and forth between the 2, or it could happen in a smooth transition, but the final outcome would be the same (see 1.) They would both end up with the same velocity, but each with a different energy.
The important part, it's units of energy that are used to calculate "vital force", both in what the masses have and what they exchange as they head towards that final point called equilibrium.
You asked for real world proof? I've done a lot of experimenting with real world masses. I've used WM2 very little. But why not let the real world speak for itself. Take a look at airplanes, jet planes, cars, forces affecting all modes of transportation, crash site analysis, etc etc etc. and compare the real world analysis techniques which use the conservation of energy to make all of that happen against the thousands upon thousands of people performing them and the thousands upon thousands of hours in which they are performed and ask yourself, if this is really wrong wouldn't it have been noticeable and spotted a long time ago? And if that's not good enough consider the thousands upon thousands of man hours that went into the testing and finalization of those techniques. Or do you think that real world scientists and physicists are all fooling themselves? And you might also want to contemplate why scientists always quote "the conservation of energy".
Finally if you really believe this is still wrong, and this goes out to you greendoor as well, get a real physicist on here with real credentials stating just why the conservation of energy is wrong. And if you do that, just to keep it honest I'll bring in one or two myself to counter those arguments.
Broli go and do some real world testing and you'll see it's not evil but actual. I have a device in fact I can post up that you can easily recreate to prove it to yourself.
meChANical Man.
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"All things move according to the whims of the great magnet"; Hunter S. Thompson.
First I fixed an angular momentum calculation problem. Then I added a what-if scenario on the right. This basiclly shows the case when linear momentum is conserved. I then added a COP calculation and how much net energy would be created starting from the initial energy that went into the system.
Finally I added some controls that allow you to customize pretty much all the main variables on the fly.
This whole simulation should be kept on hand when performing real world experiments. So you can compare the results with both the wm2d results on the left and the CoM results on the right.
You'll discover that increasing the initial angular velocity will create a lot of NET energy very fast. So this is what should be strived for in experiments to prove it beyond a shadow of a doubt. Seeing 740 000 joules (100 rad/s initial speed (955 RPM)) created in 50ms time could be impressive :D.
There you have it, completely free of charge, something that this forum doesn't like to hear so much.
This is interesting. NASA claimed that it was angular momentum that was conserved as the 3 kilogram mass unwound from the satellite in their yo-yo de-spin device. NASA quote: ‘The relatively small weights can have such a large effect since they are far from the axis of the spin, and their effect grows as the square of the length of the cables.’
WM2D claims that kinetic energy is conserved in the thought experiment being discussed, which is the same basic device.
Newton did not limit his Three Laws of Motion to only object moving in a linear path. The Law of Conservation of Momentum (which is linear Newtonian momentum) applies to objects in a circular path as well as a linear path; so Newtonian physics disagrees with both NASA and WM2D.
WM2D disagrees with NASA and Newton.
NASA disagrees with Newton and WM2D.
We have three different formulas for solving the same problem; two of the formulas or concepts are wrong.
My data shows that Newton is correct. To my knowledge The Law of Conservation of (linear Newtonian) Momentum has never been violated. Some will sight atomic physics, but we are not dealing with atomic physics. When Newtonian motion is conserved energy can be increased dramatically.
If you want to measure kilo joules of excess energy you'd need some space and some semi professional equipment.
Getting a flywheel is simple. The big challenge is building the rails. These can be linear type bearings. What you would also need is a way to measure the speed. This can be done by placing sensors or something along the rail.
A professor would snap his fingers and such a setup would be build. We however have to sweat and bleed.
