Torque question

[studiot]

Of course, but why only anticlockwise?

 

There is only angular momentum if mass is involved in the rotation.

 

Torque (in my opinion) only exists if that rotation is twisting something physical.

 

The practical experiments I drew you attention to are designed to show these ideas.

 

alternatively the classic example is the rotating garden sprinkler, these can also be fun to experiment with.

Edited October 9, 2014 by studiot

[Relative]

Of course, but why only anticlockwise?

 

There is only angular momentum if mass is involved in the rotation.

 

Torque (in my opinion) only exists if that rotation is twisting something physical.

i think applies

''torque is the cross product of lever length and force, and angular momentum is the cross product of linear momentum and distance from an origin. ''

[studiot]

The Lorenz equation has nothing to do with torque.

 

I would challenge any expert to show me a torque applied to a torque wrench or screwdriver with the above definition as the only input.

[Relative]

The Lorenz equation has nothing to do with torque.

 

I would challenge any expert to show me a torque applied to a torque wrench or screwdriver with the above definition as the only input.

what about the torque on a Euler axis?

[studiot]

Euler axes are only regular rectangular axes.

 

The ruler experiment that Bignose offered corresponds to moments (I know that modern americans call these torques) on 'Euler axes' and what happens to the ruler if you apply them?

 

Interestingly they came up in the guise of Euler instability in post#4 of this current thread about Chaos Theory.

 

http://www.scienceforums.net/topic/85959-questions-about-chaos-theory/

 

If you take a brick, book or cigarette packet, it has three Euler axes. If you hold it between your hands by opposite faces, (thus picking out an axis) and toss it into the air, spinning, then the following occurs

 

For two of the three pairs of faces the spin will be stable. (ie spin about two of the axes)

 

For one pair of faces the spin will rapidly degenerate into a wobble that gets bigger and bigger until the object tumbles instead of spinning.

 

Try it and tell me which axis this is. It is always the same one.

Edited October 9, 2014 by studiot

[Relative]

Euler axes are only regular rectangular axes.

 

The ruler experiment that Bignose offered corresponds to moments (I know that modern americans call these torques) on 'Euler axes' and what happens to the ruler if you apply them?

I am unsure what your experiment actual says to do, I think you are saying to channel out a grove, in the center of a plain, where I will slot a ruler, so it looks like an upside down T shape? then twist it by holding just the ruler in a central position?

 

[studiot]

 

The ruler experiment that Bignose offered corresponds to moments (I know that modern americans call these torques) on 'Euler axes' and what happens to the ruler if you apply them?

I am unsure what your experiment actual says to do,

 

I am unsure what your experiment actual says to do,

 

 

Bignose offered you a simple experiment in post#15 of this thread and from your favourable response I thought you had tried it out.

Have you forgotten already?

 

My experiment in the other thread had nothing to do with Euler.

Edited October 9, 2014 by studiot

[Relative]

 

Bignose offered you a simple experiment in post#15 of this thread and from your favourable response I thought you had tried it out.

Have you forgotten already?

 

My experiment in the other thread had nothing to do with Euler.

For some reason, last night I knew what exactly torque was, torque is linear force, that twists,

The center of mass always been the torque point

and i am now proper annoyed because i could of completed my G model and explained the orbit by torque

[studiot]

 

torque is linear force

 

Torque may be produced by linear force that twists, or it may not.

 

But it is not force.

 

Many have said this to you repeatedly in this thread.

Edited October 10, 2014 by studiot

[swansont]

 

and i am now proper annoyed because i could of completed my G model and explained the orbit by torque

 

When the force acts on the rotation point, there is no torque. In a circular orbit the angular momentum quite obviously does not change, which confirms the absence of a torque.

[Relative]

 

Torque may be produced by linear force that twists, or it may not.

 

But it is not force.

 

Many have said this to you repeatedly in this thread.

You can not have torque without force, force is applied to the center of mass, hence twist, torque is linear force that makes a twist.

 

When the force acts on the rotation point, there is no torque. In a circular orbit the angular momentum quite obviously does not change, which confirms the absence of a torque.

You are not accounting for individual torque of the center of masses, the lorenz force applied linear through a rotating body, Faraday discovered that even a small current could rotate a wire around mass, there is torque in energies.

F=ma still applies to energy

[studiot]

 

You can not have torque without force, force is applied to the center of mass, hence twist, torque is linear force that makes a twist.

 

 

Rubbish.

Most torques arise from couples, not forces but not even they are strictly necessary.

 

Unless you wish to tell me that the Wankel engine produces zero torque and can therefore not drive a vehicle?

 

I have told you that the physical quantity you need to consider for a massive object whirling around on the end of a rod is called moment of momentum or angular momentum.

Edited October 10, 2014 by studiot

[Relative]

 

Rubbish.

Most torques arise from couples, not forces but not even they are strictly necessary.

 

Unless you wish to tell me that the Wankel engine produces zero torque and can therefore not drive a vehicle?

 

I have told you that the physical quantity you need to consider for a massive object whirling around on the end of a rod is called moment of momentum or angular momentum.

The moment can not be produced without inertia, a leverage system transfers torque from linear into angular momentum, the initial F comes from the central point, the center of mass of the pivot system, F applied linear creating twist. There can be no momentum without F, The F is always at the center of mass.

[studiot]

 

The moment can not be produced without inertia

 

Since I would rather say something positive this is the (only) part of your last post that is correct.

 

The inertia is another name for inertial mass.

[Relative]

 

Since I would rather say something positive this is the (only) part of your last post that is correct.ere

 

The inertia is another name for inertial mass.

So you agree in torque there has to be inertial mass, so why can you not agree that a lever is just redirection of force?

The link has no direct force applied, the F is indirect

[studiot]

 

So you agree in torque there has to be inertial mass

 

No, why would I?

 

You have changed what I said, why?

I agreed with the following statement you made.

 

 

The moment can not be produced without inertia

 

Perhaps it's my eyesight but I cannot see torque mentioned.

 

I would agree, and have stated this, that torque cannot be applied without mass since all physical objects have mass at the classical scale.

 

Let me try one last time.

 

Take a screwdriver in your hand and turn it in free air.

Your hand is applying a turning effect to the handle

The screwdriver rotates as a whole

There is no twist or torsion

There is no torque

 

Now insert that screwdriver into a screwhead and turn it.

Your hand is applying a turning effect to the handle

The screwhead is applying a counter turning effect to the bit

There is twist and torsion in the shaft

That is the sitution where torque arises

 

If the turning effect is greater than the counterturning effect then the shaft will not be in equilibrium and will spin or rotate.

This is the situation where an engine develops torque and cannot occut without all the components being in place.

[Relative]

 

No, why would I?

 

You have changed what I said, why?

I agreed with the following statement you made.

 

 

Perhaps it's my eyesight but I cannot see torque mentioned.

 

I would agree, and have stated this, that torque cannot be applied without mass since all physical objects have mass at the classical scale.

 

Let me try one last time.

 

Take a screwdriver in your hand and turn it in free air.

Your hand is applying a turning effect to the handle

The screwdriver rotates as a whole

There is no twist or torsion

There is no torque

 

Now insert that screwdriver into a screwhead and turn it.

Your hand is applying a turning effect to the handle

The screwhead is applying a counter turning effect to the bit

There is twist and torsion in the shaft

That is the sitution where torque arises

 

If the turning effect is greater than the counterturning effect then the shaft will not be in equilibrium and will spin or rotate.

This is the situation where an engine develops torque and cannot occut without all the components being in place.

Not entirely true to be honest, I use a screw driver and tools most days, agreed that a free turning screw driver in fresh air has no resistance, although if you could rotate the screw driver fast enough, you create force of air,

 

 

You do realize that just turning a screw driver in a cross head screw does not work, you have to apply linear force also, you have to press down,

 

 

A screw in a raw plug, the net force of a screw in a wall plug is zero, the screw and the raw plug have equal force, the resistance to the screw turning is torque,

 

 

I apply F linear,then apply F to the twist, to undo the screw.

 

 

Every action has an opposite and equal reaction, the action is the raw plug holds the screw , I apply force and force to create a reaction, torque is been complicated when it is linear twist .

Edited October 10, 2014 by Relative

[studiot]

 

linear twist

 

Wow batman !*#!

[swansont]

You can not have torque without force, force is applied to the center of mass, hence twist, torque is linear force that makes a twist.

You are not accounting for individual torque of the center of masses, the lorenz force applied linear through a rotating body, Faraday discovered that even a small current could rotate a wire around mass, there is torque in energies.

F=ma still applies to energy

 

 

There is so much that is wrong with these statements, it's hard to figure it out. Part of this, I think, is the pop-sci effect — you've been learning a little about physics, just as people do when they read pop-sci stories, but you really haven't learned any physics. To do that, you'd have to sit down and work out some fairly simple problems, to ensure that you'd cleared up your misconceptions. But there is this tendency to immediately leap into more complex problems without a good foundation, and we get these statements that show that you do not, in fact, understand the physics.

 

You seem to imply that a force applied to the center of mass will induce a rotation. Do you have a simple example of this happening? i.e. where the only force on a uniform object is acting on its CoM, and it rotates?

 

What I suspect is that you are simply ignoring many other effects in order to come to this conclusion. This is a reason physics education starts with simple systems — so we can isolate individual effects.

[Relative]

 

 

There is so much that is wrong with these statements, it's hard to figure it out. Part of this, I think, is the pop-sci effect — you've been learning a little about physics, just as people do when they read pop-sci stories, but you really haven't learned any physics. To do that, you'd have to sit down and work out some fairly simple problems, to ensure that you'd cleared up your misconceptions. But there is this tendency to immediately leap into more complex problems without a good foundation, and we get these statements that show that you do not, in fact, understand the physics.

 

You seem to imply that a force applied to the center of mass will induce a rotation. Do you have a simple example of this happening? i.e. where the only force on a uniform object is acting on its CoM, and it rotates?

 

What I suspect is that you are simply ignoring many other effects in order to come to this conclusion. This is a reason physics education starts with simple systems — so we can isolate individual effects.

I am not ignoring anything , that is why I consider myself to be a reasonable science mind, any suttle difference can have effect. I awoke this morning , and everything was has clear day when discussing torque, and let me think, I believe I can explain it , but will need to start a speculation thread, pffff,

 

 

I cant talk open i will be closed down although my thoughts are science, and far better than some of the garbage left in speculation that are open, and have no relevance to anything, who cares how the pyramids were built, that achieves nothing.

 

Applied force to CoM, f=ma, the momentum is linear, I add different direction of F, and the momentum of the mass will be linear and rotating,

 

 

I have played snooker in my time, I understand back spin etc, applying force changes direction, always.

Edited October 10, 2014 by Relative

[studiot]

+1 swansont.

 

 

 

You seem to imply that a force applied to the center of mass will induce a rotation. Do you have a simple example of this happening? i.e. where the only force on a uniform object is acting on its CoM, and it rotates?

 

 

Bignose's ruler experiment was designed and offered to show relative the exact opposte!

Edited October 10, 2014 by studiot

[Relative]

So what torque is involved in these diagrams?

[imatfaal]

Let me try one last time.

 

Take a screwdriver in your hand and turn it in free air.

Your hand is applying a turning effect to the handle

The screwdriver rotates as a whole

There is no twist or torsion

There is no torque

 

Now insert that screwdriver into a screwhead and turn it.

Your hand is applying a turning effect to the handle

The screwhead is applying a counter turning effect to the bit

There is twist and torsion in the shaft

That is the sitution where torque arises

 

Studiot - I have not followed closely enough to find out if this is covered by your use of older UK terms and not the US terms I am familiar with - but the above is non-standard if using modern terminology

 

In the first example the screwdriver as a system goes from a situation in which it has zero angular momentum to a second state in which it has angular momentum - the net torque (in modern US terminology) is the change in angular momentum in time; there is an external net torque in the first exampe

 

In the second example - again taking the screwdriver as the system - there is no change in angular momentum (I am presuming the screw isn't turning) and by definition there is no external net torque.

[Relative]

 

Studiot - I have not followed closely enough to find out if this is covered by your use of older UK terms and not the US terms I am familiar with - but the above is non-standard if using modern terminology

 

In the first example the screwdriver as a system goes from a situation in which it has zero angular momentum to a second state in which it has angular momentum - the net torque (in modern US terminology) is the change in angular momentum in time; there is an external net torque in the first exampe

 

In the second example - again taking the screwdriver as the system - there is no change in angular momentum (I am presuming the screw isn't turning) and by definition there is no external net torque.

yes that sounds better

[swansont]

+1 swansont.

 

 

 

 

Bignose's ruler experiment was designed and offered to show relative the exact opposte!

 

I was starting simple. Just the first part of that example, where there is indeed no rotation.