| Topic: |
Science > Physics |
| User: |
"Brett" |
| Date: |
05 Jun 2004 01:47:49 PM |
| Object: |
Does this cause friction? |
If two surfaces are exactly the same and rub together, is friction
created? Please explain.
Thanks,
Brett
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| User: "Greg Neill" |
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| Title: Re: Does this cause friction? |
05 Jun 2004 02:57:52 PM |
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"Brett" <account@cygen.com> wrote in message
news:c003b25a.0406051047.2a6a7844@posting.google.com...
If two surfaces are exactly the same and rub together, is friction
created? Please explain.
One could imagine two identical pieces of sandpaper.
Rub them together, of course you get friction.
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| User: "Michael Varney" |
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| Title: Re: Does this cause friction? |
06 Jun 2004 05:18:01 PM |
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"Brett" <account@cygen.com> wrote in message
news:c003b25a.0406051047.2a6a7844@posting.google.com...
If two surfaces are exactly the same and rub together, is friction
created? Please explain.
www.google.com "how to use google"
www.google.com "do your own thinking"
www.google.com "do you own home work"
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| User: "Eric Gisse" |
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| Title: Re: Does this cause friction? |
05 Jun 2004 06:49:44 PM |
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(Brett) wrote in message news:<c003b25a.0406051047.2a6a7844@posting.google.com>...
If two surfaces are exactly the same and rub together, is friction
created? Please explain.
Thanks,
Brett
Rub 2 pieces of equal grit sandpaper together.
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| User: "floyd" |
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| Title: Re: Does this cause friction? |
05 Jun 2004 06:06:24 PM |
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(Brett) wrote in message news:<c003b25a.0406051047.2a6a7844@posting.google.com>...
If two surfaces are exactly the same and rub together, is friction
created? Please explain.
Thanks,
Brett
Yes. Tables of static and kinetic friction coefficients are available
on Google. They are useful because for pretty smooth surfaces
friction is often
nearly independent of contact area and only a function of the two
surfaces and
the normal force (how hard they are being pressed together). For
rough
surfaces the frictional forces will depend on contact area. Friction
is not a "real" force, all contact forces are electromagnetic in
nature.
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| User: "" |
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| Title: Re: Does this cause friction? |
05 Jun 2004 02:02:29 PM |
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Brett <account@cygen.com> wrote:
If two surfaces are exactly the same and rub together, is friction
created? Please explain.
Thanks,
Brett
What do you mean "exactly the same"?
Take two identical files off the shelf at the hardware store and rub
them together (quickly before the clerk throws you out).
Is there friction?
--
Jim Pennino
Remove -spam-sux to reply.
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| User: "MorituriMax" |
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| Title: Re: Does this cause friction? |
06 Jun 2004 05:35:46 PM |
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Brett wrote:
If two surfaces are exactly the same and rub together, is friction
created? Please explain.
They cannot be exactly the same, for one, and they are still seperate surfaces
with their own friction values. Unless they are "magically" frictionless that
is.
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| User: "Brett" |
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| Title: Re: Does this cause friction? |
08 Jun 2004 07:45:58 PM |
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"MorituriMax" <newage@sendarico.net> wrote in message news:<6%Mwc.39763$4x2.18691@fe2.texas.rr.com>...
Brett wrote:
If two surfaces are exactly the same and rub together, is friction
created? Please explain.
They cannot be exactly the same, for one, and they are still seperate surfaces
with their own friction values. Unless they are "magically" frictionless that
is.
If you have two surfaces that are exactly the same, shouldn't they
have the same friction values?
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| User: "Edward Green" |
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| Title: Re: Does this cause friction? |
18 Jun 2004 09:56:06 PM |
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(Brett) wrote in message news:<c003b25a.0406081645.31079500@posting.google.com>...
"MorituriMax" <newage@sendarico.net> wrote in message news:<6%Mwc.39763$4x2.18691@fe2.texas.rr.com>...
Brett wrote:
If two surfaces are exactly the same and rub together, is friction
created? Please explain.
They cannot be exactly the same, for one, and they are still seperate surfaces
with their own friction values. Unless they are "magically" frictionless that
is.
If you have two surfaces that are exactly the same, shouldn't they
have the same friction values?
There must be some undisclosed bug in your thinking about friction.
Can you explain in detail why you would expect sliding contact between
identical surfaces to be frictionless?
Let me guess: you reason the frictional force in this case will be
equal and opposite on the opposing surfaces, and thus cancel?
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| User: "Sam Wormley" |
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| Title: Re: Does this cause friction? |
08 Jun 2004 08:19:40 PM |
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Brett wrote:
"MorituriMax" <newage@sendarico.net> wrote in message news:<6%Mwc.39763$4x2.18691@fe2.texas.rr.com>...
Brett wrote:
If two surfaces are exactly the same and rub together, is friction
created? Please explain.
They cannot be exactly the same, for one, and they are still seperate surfaces
with their own friction values. Unless they are "magically" frictionless that
is.
If you have two surfaces that are exactly the same, shouldn't they
have the same friction values?
Don't forget normal force.
Number 677 #3, March 18, 2004 by Phil Schewe and Ben Stein
Ultra-Low Friction, Without Lubricants
Ultra-low friction, without lubricants, has been
observed in an experiment at the University of Basel in
Switzerland, with interesting implications for possible
nanotech applications.
The dragging of a force microscope tip across the
surface atoms of a sample (size regime of one-billionth
meter) is not unlike the motion of underground tectonic
blocks (size scale of tens of thousands of meters): in both
cases the sideways motion of one object past another
gets stuck for a while until sufficient lateral force builds
up when motion is resumed, sometimes with a jerk and
a dissipation of energy.
This "stick-slip" syndrome---the main scenario for
friction at the atomic level---can be smoothed somewhat
by lubricants, but the new experiment at Basel shows
that if the load (the object on top) is made light enough
it can slide along a surface without any friction (and
with no lubricants present), at least not at a sensitivity
level of 10-11 newtons.
According to Enrico Gnecco (41-61-267-3725,
enrico.gnecco@unibas.ch) the gliding of a force
microscope tip across a sample was observed to
undergo a transition from stick-slip to continuous
sliding, and that this be very useful in the realm of
nanoelectromechanical (NEM) devices, where
nano-sleds and nano-containers might be moved
around with negligible dissipation. (Socoliuc et al.,
Physical Review Letters, upcoming article; also see lab
website.)
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