[paul cotter]

In any discipline one will find highly educated cranks, two examples are (1) Puthoff who believes in telekinesis, telepathy, remote viewing and other woo-woo and (2) Montagnier who believes in homeopathy(there are plenty more!). If one looks far enough it is possible to find support for the craziest ideas- does that mean we should accept such nonsense? The idea of bastardising the radian into a dimensional unit is one such futile idea. So you have found "more" than twelve scientists in the last ~85 years who support these ideas while acknowledging the difficulties involved would preclude their use. This suggests it is a fringe idea, at the very best.

[alancalverd]

Do you understand the concepts of rate of change?

anyone with a driving licence obviously understands the concept. Those of us with A level maths, a PhD in physics and a pilot licence not only understand differential calculus, but live by its use. But in the case of static braking, it is clearly irrelevant.

What about angular momentum?

I teach MRI physics and the fundamentals of aircraft instrumentation. I pay a mechanic to dynamically balance my car wheels and aircraft propellors. Again, I live by understanding this stuff, and knowing others who do.
   

As the name suggests, the modern concept of torque was not recognized by ancient people.

You are confused between torque, which every engineer has recognised since the invention of the wheel, and your bizarre, ludicrous and utterly useless  redefinition of the word, the implications of which you plainly refuse to understand. 

[alancalverd]

My Neolithic predecessor Ug built a windlass to raise a bucket of water from a well. Being a physicist rather than an engineer, he used a frictionless pivot and a weightless rope. The radius of the spindle was r meters and the weight of the full bucket was F newtons. So the torque needed to raise the bucket was Fr newton meters, whether he rotated the spindle once, a hundred times, or not at all.

Then Hamdani's (great)ⁿ grandfather came along and told him that torque is an inverse function of angular displacement so the torque required to lift the bucket increased as it was rising, but magically disappeared if it stopped moving, so he didn't need a brake to stop the bucket falling back down the well.   

What is most surprising about this story is that Hamdani's line of evolution has not been eliminated by Darwinian selection.  It is remarkable that any family has survived until the 21st century without encountering rotating machinery, or at least the need to prevent it from rotating. So there is still a place for Aristotelian mechanics.

[hamdani yusuf (OP)]

You are confused between torque, which every engineer has recognised since the invention of the wheel, and your bizarre, ludicrous and utterly useless  redefinition of the word, the implications of which you plainly refuse to understand. 

You are confused between torque in modern usage and leverage, which was introduced by Archimedes millennia ago.

https://farside.ph.utexas.edu/teaching/301/lectures/node155.html

(Recall, from Sect. 9, that torque is the rate of change of angular momentum.)

[hamdani yusuf (OP)]

My Neolithic predecessor Ug built a windlass to raise a bucket of water from a well. Being a physicist rather than an engineer, he used a frictionless pivot and a weightless rope. The radius of the spindle was r meters and the weight of the full bucket was F newtons. So the torque needed to raise the bucket was Fr newton meters, whether he rotated the spindle once, a hundred times, or not at all.

Then Hamdani's (great)ⁿ grandfather came along and told him that torque is an inverse function of angular displacement so the torque required to lift the bucket increased as it was rising, but magically disappeared if it stopped moving, so he didn't need a brake to stop the bucket falling back down the well.   

What is most surprising about this story is that Hamdani's line of evolution has not been eliminated by Darwinian selection.  It is remarkable that any family has survived until the 21st century without encountering rotating machinery, or at least the need to prevent it from rotating. So there is still a place for Aristotelian mechanics.

You seem to forget that rolling down the hill at constant velocity implies zero torque.

[hamdani yusuf (OP)]

I'm quite happy dealing with people who don't know much physics, but not with someone who refuses to learn.

Between these two tables, which one is more consistent?

You don't seem to be aware of the inconsistency in current standard units of rotational quantities, as shown clearly in this table.


Compare them with the new proposed standard units, which are consistent with the relating equations.

If you still wonder why some people have proposed changes to current standard units in rotational quantities, read the tables above thoroughly, and understand what they mean and imply.

[alancalverd]

Using your definition of torque, please calculate the torque required to rotate Ug's windlass (reply #702) through one, five and ten rotations.

Using your definition of torque, please calculate the force required on the brake pads of a car  to hold it stationary on a slope.

Both calculations are  perfectly straightforward and absolutely consistent if you use the "current standard units". The implications of your proposed definitions are frankly ridiculous.

[alancalverd]

https://farside.ph.utexas.edu/teaching/301/lectures/node155.html
Quote
(Recall, from Sect. 9, that torque is the rate of change of angular momentum.)

Let this be a warning to anyone contemplating studying physics or engineering at UT. No wonder US manufacturing industry has gone down the toilet, and the doors fall off Boeing aircraft.

[hamdani yusuf (OP)]

https://farside.ph.utexas.edu/teaching/301/lectures/node155.html
Quote
(Recall, from Sect. 9, that torque is the rate of change of angular momentum.)

Let this be a warning to anyone contemplating studying physics or engineering at UT. No wonder US manufacturing industry has gone down the toilet, and the doors fall off Boeing aircraft.

I think you need to update your knowledge.

[hamdani yusuf (OP)]

Using your definition of torque, please calculate the torque required to rotate Ug's windlass (reply #702) through one, five and ten rotations.

Using your definition of torque, please calculate the force required on the brake pads of a car  to hold it stationary on a slope.

Both calculations are  perfectly straightforward and absolutely consistent if you use the "current standard units". The implications of your proposed definitions are frankly ridiculous.

You get the different unit because you assign the length unit for radius.
In my proposed unit, the length is assigned to the arc length rotational distance, thus the radius of rotation can be calculated as ∂d/∂θ.
If you rotate by one radian, the rotational distance is equal to the rotational radius. If it's one rotation, the rotational distance is equal to 2 pi times the rotational radius. But the torque is the same because that number is divided by 2 pi.
The same thing for 5 or 10 rotations.

[hamdani yusuf (OP)]

I'm quite happy dealing with people who don't know much physics, but not with someone who refuses to learn.

Between these two tables, which one is more consistent?

You don't seem to be aware of the inconsistency in current standard units of rotational quantities, as shown clearly in this table.


Compare them with the new proposed standard units, which are consistent with the relating equations.

If you still wonder why some people have proposed changes to current standard units in rotational quantities, read the tables above thoroughly, and understand what they mean and imply.

Before we debate about the difference, let's discuss about their similarities first.
The proposed new standard units are the same as current standard units for angle, angular velocity, and angular acceleration. Also for work and power. Units for kinetic energy and potential energy are also still the same.

[alancalverd]

You still haven't answered the questions, because you can't.

If τ= Fr, then τ is constant however many turns Ug makes of the windlass, which is obvious and demonstrable, from the horse-powered well (there was one in my back garden) to the weight-driven cuckoo clock.

If you make τ = Fr/θ, then τ decreases from infinity towards zero as the bucket rises or the clock hands move, which is nonsense.

If you define τ as Iα, then assemble a nut and bolt with a tightening specification of τ_max, you can flick the nut with your finger and get a very high immediate value of α, but whilst you might pass a University of Texas exam with that definition, it won't hold the door onto an airplane built in Seattle or St Louis, as recently demonstrated.

[hamdani yusuf (OP)]

You still haven't answered the questions, because you can't.

If τ= Fr, then τ is constant however many turns Ug makes of the windlass, which is obvious and demonstrable, from the horse-powered well (there was one in my back garden) to the weight-driven cuckoo clock.

If you make τ = Fr/θ, then τ decreases from infinity towards zero as the bucket rises or the clock hands move, which is nonsense.

If you define τ as Iα, then assemble a nut and bolt with a tightening specification of τ_max, you can flick the nut with your finger and get a very high immediate value of α, but whilst you might pass a University of Texas exam with that definition, it won't hold the door onto an airplane built in Seattle or St Louis, as recently demonstrated.

You are confused because my formula is not F r/θ. I don't know where you got that from.
My formula  is τ = F ∂d/∂θ, where ∂d is rotational displacement and ∂θ is the corresponding rotational angle.
Note that ∂d/∂θ = rotational radius, by definition. This is the general form, where the radius of rotation doesn't have to be constant during the rotation.
So, assuming that the rotational radius is constant, when you double the rotational displacement, the rotational angle is also doubled, thus the torque is the same as before.

If τ doesn't equal Iα, how do you relate torque to angular acceleration?
What do we get when rotational inertia (aka moment of inertia) is multiplied by angular acceleration?

[hamdani yusuf (OP)]

I'm quite happy dealing with people who don't know much physics, but not with someone who refuses to learn.

Between these two tables, which one is more consistent?

You don't seem to be aware of the inconsistency in current standard units of rotational quantities, as shown clearly in this table.


Compare them with the new proposed standard units, which are consistent with the relating equations.

If you still wonder why some people have proposed changes to current standard units in rotational quantities, read the tables above thoroughly, and understand what they mean and imply.

Before we debate about the difference, let's discuss about their similarities first.
The proposed new standard units are the same as current standard units for angle, angular velocity, and angular acceleration. Also for work and power. Units for kinetic energy and potential energy are also still the same.

Now let's take a look at their difference. First, rotational inertia, I.
The current standard unit for I is kg.m^2, which is based on the equation I = mass times rotational radius squared.
I = m R^2
The current standard unit for mass is kilogram, while the current standard unit for rotational radius is meter.
But don't forget that rotational inertia is also involved in many other equations.
I = L/ω
I = τ/α
I = 2 Ek / ω^2
Let's use the last equation, because we have the same agreed units for kinetic energy and angular velocity, thus there should be no dispute to the result.
Standard unit for kinetic energy is kg m^2 s^-2
Standard unit for angular velocity is rad s^-1,
thus ω^2 has standard unit rad^2 s^-2
Thus the Standard unit for rotational inertia should be kg m^2 rad^-2

Now we need to reconcile with the equation used for the current standard unit for rotational inertia.
I = m R^2 = 2 Ek / ω^2
R^2 = I/m
R = √(I/m)
Thus the standard unit for rotational radius should be meter per radian.

[alancalverd]

If τ doesn't equal Iα, how do you relate torque to angular acceleration?

Cart before horse! If you apply a torque τ to a freely rotating body I then it will accelerate at α = τ/I. But if you apply the same torque to a body that is not free to rotate, it won't.

Therefore Iα is a potential effect of torque, not a definition of it.

I covered this point several posts ago.

You are confused because my formula is not F r/θ.

Oh yes it is:

Thus the standard unit for rotational radius should be meter per radian.

[Bored chemist]

What's the unit of Torque?
I have been away over Easter; has it changed?

[hamdani yusuf (OP)]

What's the unit of Torque?
I have been away over Easter; has it changed?

Not yet.

A standard is a social construct. What's accepted in a society may not be accepted in another society. Just look at the metric system.

[hamdani yusuf (OP)]

If τ doesn't equal Iα, how do you relate torque to angular acceleration?

Cart before horse! If you apply a torque τ to a freely rotating body I then it will accelerate at α = τ/I. But if you apply the same torque to a body that is not free to rotate, it won't.

Therefore Iα is a potential effect of torque, not a definition of it.

I covered this point several posts ago.

You are confused because my formula is not F r/θ.

Oh yes it is:

Thus the standard unit for rotational radius should be meter per radian.

Why isn't it free to rotate?
Is F=m.a?

If τ doesn't equal Iα, how do you relate torque to angular acceleration?
What do we get when rotational inertia (aka moment of inertia) is multiplied by angular acceleration?

What is the unit for arc length of a circle?
What is the unit for circumference of a circle?

[hamdani yusuf (OP)]

Remove all "rads" and the table becomes consistent.

What's your unit for rotational angle, angular velocity, and angular acceleration?

You can replace radian with another unit for angle, like degree, turn or rotation. But you can't simply remove it. You will lose track if you have to convert it later to any other units.

[paul cotter]

NO.