Can I set my own bindings?

The Real Bev wrote:
Walt wrote:
The Real Bev wrote:
Walt wrote:

...And someday I plan to get the other two volumes
of Feynman....

There are THREE? I thought there were only two.

Yup. Three. The first volume is on mechanics & thermo , the second
on E&M and the third on quantum.

See http://en.wikipedia.org/wiki/The_Fey...res_on_Physics

I've got volume 2, which I picked up at a garage sale for a buck a
decade or two ago. I've been looking for other underpriced stray
volumes ever since. I call this the Bev method of library acquisition.

We cleaned out a pile of books. We filled a 100-gallon recycling
container with stuff like old DOS manuals and other books that nobody
will ever want to read or buy or even be given. We gave (while they
were closed, of course) an equivalent amount to the library. Books
proliferate beyond all possibility of utility.

I think they breed. ****ing books. Literally.

Allen has Vol 1. Friend has Vol 2. Both are keeping theirs. This has
caused a certain amount of friction.

Friction? That's covered in volume 1.


A friend told me a Feynman story yesterday.


I don't have any Feynman stories to share. )c:

The best I can do is this clip of Bjork on the phone:

http://www.negrophonic.com/wp-conten...bjorkdiddy.gif

//Walt

Alan Baker wrote:
In article ,
VtSkier wrote:

frankenskier wrote:
On Feb 19, 4:46 pm, VtSkier wrote:
Walt wrote:
VtSkier wrote:
Walt wrote:
I cannot find a single definition of torque that
doesn't require motion that is either happening
or is about to happen.
That's odd, since I've only posted it about 5 times. Here it is again:
T = r x F
where F is the force and r is the moment arm vector.
Now, what, exactly, is in motion here? A force, acting on a moment arm
produces torque. We agree that it's possible for a force to exist
without motion. The above definition shows that a stationary force will
produce torque.
I really can't make this any clearer.
If I didn't know you better I'd say that you were just trolling.
//Walt
It goes to the definition of VECTOR. My reading, which I
posted, it that a vector has magnitude and direction.
Those are the qualities which create a vector, no?

Magnitude is usually expressed as a unit of length.

Force is expressed as a unit like pounds or newtons.
Force, by this definition is static. It takes
movement to make force into work. Or torque.

If you multiply a unit by another unit, you have
created yet a third unit with the first two units
as components of the third.

If you multiply a force (weight) unit by a length
unit you have a third unit that has both weight
and length as components.

if the first two units were pounds and feet the
third unit will be pound-feet. This is a unit
that requires that a force be moved a distance.
If you specify the direction of the distance
and/or add leverage that unit is called TORQUE
as opposed to simply WORK. But the force still
has to move a distance.- Hide quoted text -

- Show quoted text -
On this one, sorry but you're just wrong. Consistently wrong. As in,
you've been wrong every single time, on every post in this thread.

Except for the few instances where you've agreed with Walt.
Oh? Well so far nobody has been able to show me where I'm wrong.

You included. You've simply said that I'm wrong and I'll discount
your statement until you can back it up.

Walt at least has been very patient in trying to show me by
his words and others (cites) where I'm wrong. And I STILL
haven't gotten it yet.

Klaus chimed in to try to shed a little light with his
explanation of component torque which may well be where I've
been trying to go.

It's very hard for me to say that the following is a false
statement:

"Total torque is zero, therefore there is no torque."

Component torque, WTF does that mean? A few more words
would be helpful here. Does it mean that there is a
component OF torque being applied? Since there are
only two parts to torque (at least in the case of
tightening or loosening a nut), force and vector,
does it mean that force only is being applied to the
lever arm which creates the vector until the nut moves
and the vector exists?

Torque is analogous to force in linear motion.

Yes, I'm finally understanding the use of the terms. That's
been my hangup all along.

Would you say that you are exerting no force on an object if you're
pushing against it, but it doesn't move? No.

Force yes, work no. Same with torque, I can apply torque with
no movement and so no work is performed.

You'd be exerting a force, but something else must be exerting a force
in the opposite direction to balance the total force on the object.

Walt wrote:
The Real Bev wrote:

A friend told me a Feynman story yesterday.


I don't have any Feynman stories to share. )c:

Actually, maybe I do.

WWRFD?

http://www.wellingtongrey.net/miscellanea/archive/2006-12-25-what-would-richard-feynman-do.html


//Walt

In article ,
says...
Walt wrote:
VtSkier wrote:

Here's a more visceral example: pick up a brick and hold it straight
out in front of you with your arm horizontal. Hold it still. Then
please try to explain, without allowing the brick to move, how there
is no torque since there is no motion.

There is FORCE but no TORQUE

Ok. Change the brick out for a ski. Grasp it by the binding and hold it
vertically. Not that hard, is it?

Now grasp it by the tail and (try to) hold it horizontally. Much
harder, right?

Why? What makes one so much harder than the other? The force hasn't
increased, since the ski weighs the same as it did before.

So what makes it so much harder? HINT: torque. I double dog dare you
to hold a ski like that and tell me that you don't feel the difference.

Of course there is a difference. The difference is LEVERAGE and
LEVERAGE is a component of TORQUE. See
http://www.lightandmatter.com/html_b...ch05/ch05.html
which is quoted in a post a little farther down the list.

Torque is a twisting force. Torque will produce motion in the absence of
an equal and opposite resistive torque; but will produce no motion
otherwise.

Consider a rusted-on wheel nut (say, on an '80 Volvo wagon driven to and
from a ski mountain on which road salt is regularly applied). Torque
can be applied to the wheel nut with no resulting motion, up to the
level of torque where the rust breaks loose or something else finally
breaks.

Java

In article ,
klaus wrote:
Jeff Davis wrote:
In article ,
klaus wrote:
Jeff Davis wrote:

The slab creeps before it releases and stores elastic energy.

Yes. But this has little to do with kinetic energy. Creep is
quasi-static. velocities by difinition are negligible.

We're measuring that movement. It's observable. We can calculate a
value for v and plug it in to your equation and calculate a real value.

No you can't. As long as the slab is in place, a change of elasticity
does not imply motion. Internal stress may increase, but that doesn't
mean it moves. Only when the boundary conditions change does motion
occur, and this is independent of elasticity other than reaching thee
breaking point of internal stress and the brittle qualities of the
slab..

The slab stores elastic energy as it creeps. The velocity of the creep
is measureable, and certainly wasn't negligible to that snowboarder killed
a couple of years ago down in your neck of the woods. I agree that a change
in elasticity does not imply motion. Motion implies motion, and we've
measured it.

The boundry condition change, (I think we're talking about slab release
here,) in the case of the snowboarder was exacerbated by the skiers who
successfully descended that slope before him. We can measure the movement
of the slab in response to the weight of one skier or snowboarder. We can
also measure the rebound of the slab over time as it attempts to regain
its original posistion. We can measure the cumulative effect of the weight
of several snowboarders or skiers on a given sample of slab, and we can
make predictions regarding the failure of the weak layer below.

If it is a slab, it never lost it. Much. Only where it breaks does the
elasticity change. Elasticity does not change instantaneously.

Much.

Nice anallogy on the spring breaking. You picked right
up on what I was questioning.

The interface of the spring to the anchor does not effect the spring
constant of the spring.

I asked a fairly open question in an attempt to initiate some discussion.
Climax avalanches creep, store elastic energy, gain potential energy,
exibit kinetic energy, (albeit, due to minute movement), then release
with the weight of the last snowflake.

The, "7th skier problem," killed a guy who was snowboarding a slope others
had descended safely. I got, "7th Skier Problem," from Robbie Fuller, who
is studying, elasticity, elastic energy storage, and measuring these
effects in the field. I don't know if that's accepted terminology outside
the American Avalanche Institute. I don't care either.

I think klaus' "No," didn't consider all the variables of a dynamic snowpack.
And the discussion beats the **** out of, "No you didn't."; "Yes I did."

I made you think klaus. That's all I want this thread to do. It isn't a
competition to me. It's a discussion with substance.
--
According to John Perry Barlow, "Jeff Davis is a truly gifted trouble-maker."

In article ,
VtSkier wrote:

Alan Baker wrote:
In article ,
VtSkier wrote:

frankenskier wrote:
On Feb 19, 4:46 pm, VtSkier wrote:
Walt wrote:
VtSkier wrote:
Walt wrote:
I cannot find a single definition of torque that
doesn't require motion that is either happening
or is about to happen.
That's odd, since I've only posted it about 5 times. Here it is again:
T = r x F
where F is the force and r is the moment arm vector.
Now, what, exactly, is in motion here? A force, acting on a moment arm
produces torque. We agree that it's possible for a force to exist
without motion. The above definition shows that a stationary force will
produce torque.
I really can't make this any clearer.
If I didn't know you better I'd say that you were just trolling.
//Walt
It goes to the definition of VECTOR. My reading, which I
posted, it that a vector has magnitude and direction.
Those are the qualities which create a vector, no?

Magnitude is usually expressed as a unit of length.

Force is expressed as a unit like pounds or newtons.
Force, by this definition is static. It takes
movement to make force into work. Or torque.

If you multiply a unit by another unit, you have
created yet a third unit with the first two units
as components of the third.

If you multiply a force (weight) unit by a length
unit you have a third unit that has both weight
and length as components.

if the first two units were pounds and feet the
third unit will be pound-feet. This is a unit
that requires that a force be moved a distance.
If you specify the direction of the distance
and/or add leverage that unit is called TORQUE
as opposed to simply WORK. But the force still
has to move a distance.- Hide quoted text -

- Show quoted text -
On this one, sorry but you're just wrong. Consistently wrong. As in,
you've been wrong every single time, on every post in this thread.

Except for the few instances where you've agreed with Walt.
Oh? Well so far nobody has been able to show me where I'm wrong.

You included. You've simply said that I'm wrong and I'll discount
your statement until you can back it up.

Walt at least has been very patient in trying to show me by
his words and others (cites) where I'm wrong. And I STILL
haven't gotten it yet.

Klaus chimed in to try to shed a little light with his
explanation of component torque which may well be where I've
been trying to go.

It's very hard for me to say that the following is a false
statement:

"Total torque is zero, therefore there is no torque."

Component torque, WTF does that mean? A few more words
would be helpful here. Does it mean that there is a
component OF torque being applied? Since there are
only two parts to torque (at least in the case of
tightening or loosening a nut), force and vector,
does it mean that force only is being applied to the
lever arm which creates the vector until the nut moves
and the vector exists?

Torque is analogous to force in linear motion.

Yes, I'm finally understanding the use of the terms. That's
been my hangup all along.

Would you say that you are exerting no force on an object if you're
pushing against it, but it doesn't move? No.

Force yes, work no. Same with torque, I can apply torque with
no movement and so no work is performed.


By Jove, I think you've got it!

:-)


You'd be exerting a force, but something else must be exerting a force
in the opposite direction to balance the total force on the object.


--
"The iPhone doesn't have a speaker phone" -- "I checked very carefully" --
"I checked Apple's web pages" -- Edwin on the iPhone and how he missed
the demo of the iPhone speakerphone.

Alan Baker wrote:

Force yes, work no. Same with torque, I can apply torque with
no movement and so no work is performed.


By Jove, I think you've got it!


Great. Now we can move on to precession. :0

-klaus

klaus wrote:
Alan Baker wrote:
Force yes, work no. Same with torque, I can apply torque with
no movement and so no work is performed.

By Jove, I think you've got it!


Great. Now we can move on to precession. :0

-klaus

Are we speaking of the precession of the equinoxes and
our recent movement into the age of Aquarius?

On Feb 21, 6:56 pm, (Jeff Davis) wrote:
In article .com,

Richard Henry wrote:
On Feb 21, 4:07 pm, (Jeff Davis) wrote:
The slab creeps before it releases and stores elastic energy. It most
certainly has kinetic energy due to your own equation. Nice to have an
intelligent conversation relevant to skiing.

"Elasticity" and "elastic energy" are not the same thing.

No **** Sherlock. Where did I type that? Thanks for the hot ****ing tip
Dickie.

Just trying to help. You seemed to be confused.

"Creep", as the term is used in mechanical and civil engineering
studies of materials, is an _inelastic_ deformation of a material
caused by a stress applied beyond the elastic yield strength of the
material. The deformation is permanent (in the sense that it can't
"rebound" to its previous state) and accumulates over time if the
stress is continually applied. No energy is being stored - the energy
is consumed as work in altering the shape and/or internal structure of
the material involved.

Richard Henry wrote:
On Feb 21, 6:56 pm, (Jeff Davis) wrote:
In article .com,

Richard Henry wrote:
On Feb 21, 4:07 pm, (Jeff Davis) wrote:
The slab creeps before it releases and stores elastic energy. It most
certainly has kinetic energy due to your own equation. Nice to have an
intelligent conversation relevant to skiing.
"Elasticity" and "elastic energy" are not the same thing.
No **** Sherlock. Where did I type that? Thanks for the hot ****ing tip
Dickie.

Just trying to help. You seemed to be confused.

"Creep", as the term is used in mechanical and civil engineering
studies of materials, is an _inelastic_ deformation of a material
caused by a stress applied beyond the elastic yield strength of the
material. The deformation is permanent (in the sense that it can't
"rebound" to its previous state) and accumulates over time if the
stress is continually applied. No energy is being stored - the energy
is consumed as work in altering the shape and/or internal structure of
the material involved.

I always thought "creep" was when a project increased in scope
as the life of the project went forward.

That is, after the contract has been let, the contractor (or
architect, or owner) finds more related to the project that
"must" be done.