Does it really work? [Answered - No]

[D H]

You are once again drawing your boundaries incorrectly, you are not looking at the whole picture, and you are being very unclear. I realize there is a language problem here, but your problems transcend language boundaries. What do you mean by "Would human gains different momentums to the surface?" If you mean the change in the human's momentum, they are the same in both cases. If you mean the momentum transfered to the surface, of course these are different. Which do you mean?

[ABV]

I am pretty sure (but I could be wrong) he meant by "Would human gains different momentums to the surface?" to mean transferred momentum to the surface due to the continuous force over the time period. . He is apparently ignoring the forward traction force (a backwards force on the surface) that is triggered by the slowing of the body.

And again. The initial condition is no slippery.

With slippery - yes. Each linear momentum frame will decrease a rolling body momentum and do slipping for reducing a angular velocity and momentum.

But in this case this is continuous stopping force and no slippery at all.

[D H]

What do you mean by "no slippery at all"?

 

Thread moved to pseudoscience.

[ABV]

You are once again drawing your boundaries incorrectly, you are not looking at the whole picture, and you are being very unclear. I realize there is a language problem here, but your problems transcend language boundaries. What do you mean by "Would human gains different momentums to the surface?" If you mean the change in the human's momentum, they are the same in both cases. If you mean the momentum transfered to the surface, of course these are different. Which do you mean?

 

The second one – transferred momentum from rolling body to surface through human. Second is yes. Good.

Otherwise. The human will transfer different surface momentums in these cases to a rolling body to reach velocity V. And different momentums will transfer back during deceleration time. And pair acceleration/deceleration for these rolling bodies must be identical.

I1>I2 - moment of inertia

Pa1>Pa2 and Pd1>Pd2

Pa1=Pd1 and Pa2=Pd2

Correct?

 

 

 

Sorry about my language (:

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What do you mean by "no slippery at all"?

 

Thread moved to pseudoscience.

 

This is normal a physics questions. Why pseudoscience?

[J.C.MacSwell]

And again. The initial condition is no slippery.

With slippery - yes. Each linear momentum frame will decrease a rolling body momentum and do slipping for reducing a angular velocity and momentum.

But in this case this is continuous stopping force and no slippery at all.

 

The traction force reduces the angular momentum of the body without any slipping. It is opposite the force the human applies to the body but is applied at surface level. Please take time and care with your wording. I am often guessing as to exactly what you mean.

 

When a primary braking or accelerating force is applied at the axle, why do you continue to ignore the force of traction that is triggered? It is different for each accelerating or decelerating body depending on the moment of inertia of the body and rate of translational (linear) acceleration/deceleration

Edited June 9, 2009 by J.C.MacSwell

[ABV]

This barely qualifies as pseudoscience, let alone real science.

 

Thread moved.

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A big part of your problem, ABV, is that you are not specifying the problem clearly. This includes properly drawing system boundaries, which is the chief source of your problems to date.

 

Here you have not fully the specified initial conditions and the initial conditions are contradict your equations of motion. Is the body initially rolling or sliding? You didn't say. Is the object rolling without slipping? I guess that is what "no rolling resistance" means. Is the object rolling rolling up or down an incline or rolling on a flat surface? You didn't say.

 

If the object is initially slipping, the dynamic frictional forces will do two things: It will reduce the object's kinetic energy and it will make the object start rolling.

 

If the object is rolling without slipping, it will keep on rolling forever. Why? The velocity at the contact point is zero. The friction needed to keep the body rolling does zero work. Zero work = zero change in energy.

 

I clearly understand what I want, but it hard to explain it to you. I’m sorry. I try to do abstract in a few forces and use simple conditions. Unfortunately, during this discussion I did many changes into doc. This may be confusing everyone a lot. But I’m not going to break any law without facts or logical explanation. I try to explain my vision to you. And if it’s wrong – understand why. I have to put back my doc close to original and start new topics again. Sorry, but I have to find a truth. And I’m not going to use any pseudo theories.

[D H]

And I’m not going to use any pseudo theories.

Then you should learn some real ones. You have not discovered "an antigravity, a time machine and open door to a deep space". You have discovered nonsense.

[ABV]

The traction force reduces the angular momentum of the body without any slipping. It is opposite the force the human applies to the body but is applied at surface level. Please take time and care with your wording. I am often guessing as to exactly what you mean.

The main idea was to understand if little human transfer momentums (surface to rolling body and backwards) differently or not, for rolling bodies with same initial velocity and different moment of inertia.

[ABV]

Then you should learn some real ones. You have not discovered "an antigravity, a time machine and open door to a deep space". You have discovered nonsense.

 

Well, I'll remove it.

I didn't understand it may confuse you.

[J.C.MacSwell]

The main idea was to understand if little human transfer momentums (surface to rolling body and backwards) differently or not, for rolling bodies with same initial velocity and different moment of inertia.

 

 

For translational momentum:

 

It is different, but exactly compensated for by the traction force.

 

For Energy:

 

It is different. They have different kinetic energies and they expend different energies.

 

For angular momentum: Less straight forward than the other two above. Just don't think of this as a source of energy, or translational momentum. It is neither.

[mooeypoo]

Well, dang. I don't have the authority to merge a thread with another thread in the pseudoscience sub forum.

 

Threads merged.

 

ABV, please stick to this thread with your hypotheses on the same subject. Also, take into account that there's a reason D H is considered "Expert", and that reason isn't merely us playing around with user titles.

 

Please avoid spamming the forum and stick to one thread per theory.

[ABV]

Threads merged.

 

ABV, please stick to this thread with your hypotheses on the same subject. Also, take into account that there's a reason D H is considered "Expert", and that reason isn't merely us playing around with user titles.

 

Please avoid spamming the forum and stick to one thread per theory.

 

The tread disappeared at first time and I opened another. Sorry about it. But I would like to see/get some notifications.

[mooeypoo]

There was supposed to be a note in the other forum about the thread being moved. If it didn't appear, it was probably some technical glitch.

 

In any case, it's all sorted out now.. so you the debate can continue uninterrupted.

 

Enjoy!

 

~moo

[ABV]

For translational momentum:

 

It is different, but exactly compensated for by the traction force.

 

For Energy:

 

It is different. They have different kinetic energies and they expend different energies.

 

For angular momentum: Less straight forward than the other two above. Just don't think of this as a source of energy, or translational momentum. It is neither.

 

No, no extra energy as source

The bottom line is, a little human transfers a different momentum for rolling bodies with different (moment of inertia/full kinetic energy). Even if mass, initial velocity, and veocity frame are equal. Correct?

[J.C.MacSwell]

No, no extra energy as source

The bottom line is, a little human transfers a different momentum for rolling bodies with different (moment of inertia/full kinetic energy). Even if mass, initial velocity, and veocity frame are equal. Correct?

 

It is different, but exactly compensated for by the traction force. So effectively no.

 

What do you mean by velocity frame? Frame of reference?

[ABV]

It is different, but exactly compensated for by the traction force. So effectively no.

 

This is very important for me.

If I take 2 rolling bodies with different moment of inertia but same mass and radius. And try to accelerate them with same force to same velocity, but different acting time and distance. I will transfer a different momentum to the track, because rolling bodies have a different full kinetic energy. Correct?

 

 

What do you mean by velocity frame? Frame of reference?

I meant dV=V1-V0 for example. I out case 0-V = -V deceleration. But it was extra condition.

[mooeypoo]

This is very important for me.

If I take 2 rolling bodies with different moment of inertia but same mass and radius.

I might be missing something here, but moment of inertia is well defined to be dependent on both radius and mass:

[math]I=\int r^2 dm[/math]

(http://en.wikipedia.org/wiki/Moment_of_inertia#Definition)

 

So if you're taking two bodies with the same mass and radius, how could they have different moments of inertia?

[ABV]

I might be missing something here, but moment of inertia is well defined to be dependent on both radius and mass:

[math]I=\int r^2 dm[/math]

(http://en.wikipedia.org/wiki/Moment_of_inertia#Definition)

 

So if you're taking two bodies with the same mass and radius, how could they have different moments of inertia?

 

Easy.

You would look on my site:

http://knol.google.com/k/alex-belov/paradox-of-classical-mechanics/1xmqm1l0s4ys/3#

 

Let say one rolling body concentrate mass into disk center with small radius r and other part of disk to external R is weightless.

Another opposite rolling body is a thin ring, which concentrate a mass on external radius only.

[D H]

The two objects have different energy. Work is energy. The human has to do more work to bring the object with more kinetic energy to a stop.

 

So, what happens to the linear and angular momentum that was initially stored in the object and the human? Simple: It was transfered to whatever the object was rolling on / the human was sliding on.

 

What about energy? It's conserved also. Humans can't conjure up force out of the clear blue sky. (Superman doesn't count. He's not human and he doesn't do Lagrange multipliers...for him there are no constraints). That force presumable arises from the human sliding on the surface. Friction converts kinetic energy to thermal energy. Energy is still conserved, just not in a useful way.

 

Note: The frictional force of the human's feet with the ground is greater than the force the human applies to the rolling object. The human is coming to a stop as well.

[ABV]

The two objects have different energy. Work is energy. The human has to do more work to bring the object with more kinetic energy to a stop.

 

So, what happens to the linear and angular momentum that was initially stored in the object and the human? Simple: It was transfered to whatever the object was rolling on / the human was sliding on.

 

What about energy? It's conserved also. Humans can't conjure up force out of the clear blue sky. (Superman doesn't count. He's not human and he doesn't do Lagrange multipliers...for him there are no constraints). That force presumable arises from the human sliding on the surface. Friction converts kinetic energy to thermal energy. Energy is still conserved, just not in a useful way.

 

Note: The frictional force of the human's feet with the ground is greater than the force the human applies to the rolling object. The human is coming to a stop as well.

 

Thank you for explanation.

Let's look a bit close to momentum, which human transfer from rolling body to surface.

Let's say a little human base on cart and push a rolling body. Base on law of momentum conservation, the human takes same momentum as a rolling body.

So, if the human will push another rolling body with highest moment of inertia the previous one, he will take highest momentum to. Correct?

[J.C.MacSwell]

I might be missing something here, but moment of inertia is well defined to be dependent on both radius and mass:

[math]I=\int r^2 dm[/math]

(http://en.wikipedia.org/wiki/Moment_of_inertia#Definition)

 

So if you're taking two bodies with the same mass and radius, how could they have different moments of inertia?

 

Different mass distribution.

[mooeypoo]

Different mass distribution.

Yup, true, I didn't think about it.

[J.C.MacSwell]

The two objects have different energy. Work is energy. The human has to do more work to bring the object with more kinetic energy to a stop.

 

So, what happens to the linear and angular momentum that was initially stored in the object and the human? Simple: It was transfered to whatever the object was rolling on / the human was sliding on.

 

What about energy? It's conserved also. Humans can't conjure up force out of the clear blue sky. (Superman doesn't count. He's not human and he doesn't do Lagrange multipliers...for him there are no constraints). That force presumable arises from the human sliding on the surface. Friction converts kinetic energy to thermal energy. Energy is still conserved, just not in a useful way.

 

Note: The frictional force of the human's feet with the ground is greater than the force the human applies to the rolling object. The human is coming to a stop as well.

 

I would say that is somewhat misleading with regard to the angular momentum, to say it is simply transferred to what it is rolling on. It is often not obvious how it is conserved IMO.

 

For linear momentum it is relatively straight forward. In, say, a 2 body system, one must gain what the other loses.

 

For angular momentum one must look at the relationship between the two (or more) bodies to see that angular momentum is conserved.

Edited June 9, 2009 by J.C.MacSwell

[ABV]

I would say that is somewhat misleading with regard to the angular momentum, to say it is simply transferred to what it is rolling on. It is often not obvious how it is conserved IMO.

 

For linear momentum it is relatively straight forward. In, say, a 2 body system, one must gain what the other loses.

 

For angular momentum one must look at the relationship between the two (or more) bodies to see that angular momentum is conserved.

 

In case with a little humans, same rolling bodies masses, velocities and radiuses. The transferred momentum through little human will be a different for rolling bodies with different moment of inertia.

Correct?

[J.C.MacSwell]

In case with a little humans, same rolling bodies masses, velocities and radiuses. The transferred momentum through little human will be a different for rolling bodies with different moment of inertia.

Correct?

 

For the same force?

 

For the same time?

 

Transferred to the rolling body, or to the ground, or both?