Talk:Coefficient of friction

Confusion

This article might reinforce the common confusion that the normal force is always determined only by the weight of an object. All forces on an object must be considered.—Preceding unsigned comment added by Starwed (talk • contribs)

Are you sure? On the bottom it says that it may include other forces. --Explodicle 13:46, 25 August 2006 (UTC)[reply]

Free body diagram

Old discussion of an illustration that is no longer used in the article.

The following discussion has been closed. Please do not modify it.

I don't like the diagram (). The forces should all pass through a single point. The way it's drawn, there's a net torque on the body, which would cause an angular acceleration. Also, in the diagram, the normal force is labelled N, while in the caption, it's labelled R. Rracecarr 15:12, 12 February 2007 (UTC)[reply]

But since it's modelled as a particle don't all forces have to be through a single point? So it doesn't really matter where they're drawn from. -Grimboy (talk) 12:57, 18 January 2008 (UTC)[reply]

It's easy to draw the diagram without the torque, so why not do it? Moot point, really, because for many months the version in the article has been correct.Rracecarr (talk) 13:09, 18 January 2008 (UTC)[reply]

I've changed the free body force diagram so the forces are from the center of mass, which is how forces are usually represented in this situation (inclined planes). Clark (talk) 08:23, 29 March 2008 (UTC)[reply]

Duplicates duplicates

A lot of stuff here duplicates what's on friction. And within this article, the same info is presented twice: once at the top, and again under Static & Kinetic friction. Thoughts on ruthless deletion? Querl 06:37, 19 February 2007 (UTC)[reply]

Clarifying - I mean ruthless deletion of redundant content, not of the article itself. Querl 06:41, 19 February 2007 (UTC)[reply]

i hate this webite so i am going to tell you this was on my 12th grade report and i got an a+ so take this advice this friction is the controller and accelorator of the dependable so i am demonstraring that everyone makes mistakes everyone gets that way well bak to this the accelorator of the surfaces of contract —Preceding unsigned comment added by 76.173.143.73 (talk) 05:05, 15 November 2007 (UTC)[reply]

Values?

Why are there no values listed for the coefficient of friction? If it is a constant, wouldn't it be helpful to list some values? - Katami (talk) 01:35, 23 January 2008 (UTC)[reply]

German wikipedia

If you take a look at the German version of the article, you'll see in the "Häufige Irrtümer" section that the "µ is always lesser than 1" myth is debunked. It would be interesting to see something similar here. 89.201.132.205 (talk) 14:42, 27 March 2008 (UTC)[reply]

Frequent Mistakes

This does not look like an improvement: "having a µ > 1 merely implies that the minimum force required to move an object along the plane along which the friction acts, is greater than the reaction force of the plane on the object."

The repeated "along" seems awkward, and which component of the reaction force is meant? Not all of it, right? -AndrewDressel (talk) 02:39, 28 May 2008 (UTC)[reply]

kinetic friction and static friction depend on pair surfaces in contact.friction forces are on both. they have to work together for an object to move —Preceding unsigned comment added by 71.105.159.49 (talk) 02:00, 24 September 2008 (UTC)[reply]

resultant force

In the lead section it says: "The friction force is directed in the opposite direction of the resultant force acting on a body. " Isn't that wrong? Wouldn't the resultant force include the normal force component, which is not friction? -- Another Stickler (talk) 21:39, 18 December 2008 (UTC)[reply]

It is not clear to what the resultant in that sentence refers. It can't mean the sum of all the forces acting on the body, because that would include friction. Perhaps it means the sum of all the forces except friction. In that case, it is correct. -AndrewDressel (talk) 23:47, 18 December 2008 (UTC)[reply]

That's not correct either because it still could include the normal force components pressing the surfaces together. This is the only page relating to friction that I've seen using the term "resultant force". Perhaps it shouldn't. -- Another Stickler (talk) 01:32, 20 December 2008 (UTC)[reply]

Of course it includes the normal force components pressing the surfaces together. That's what the resultant force is. It turns out that these normal force components are equal and opposite and so cancel out. What remains is the component parallel to the surface and that friction opposes. Resultant is a convenient way to express all that. -AndrewDressel (talk) 18:23, 20 December 2008 (UTC)[reply]

If "resultant force" doesn't include all forces then the article needs to list the forces included, in which case the additional step of summing the listed forces into a resultant vector is unnecessary. -- Another Stickler (talk) 00:06, 21 December 2008 (UTC)[reply]

normal friction possibly confusable with normal force

In the lead section, it says "...an automobile making a turn is subject to friction acting perpendicular to the line of motion (in which case it is said to be 'normal' to it)". While "normal" may be a synonym for perpendicular, this description of friction as "normal" may cause confusion with the "normal force" which is perpendicular to both the (curving) line of motion and the line of friction. -- Another Stickler (talk) 22:00, 18 December 2008 (UTC)[reply]

Overlap

There appears to be a lot of overlap between this article and the friction article. I'd like to cut out most of the description of friction from this article and leave it to the main article on the subject. Objections? -AndrewDressel (talk) 18:33, 20 December 2008 (UTC)[reply]

Agreed! Maybe I'm stretching too far here, but is this article really needed? Can it not be merged into the friction article? More than half of it is just a rehashing of the friction article. There's already a coefficient of friction section in the friction article where it could be merged. What do you think? Wizard191 (talk) 19:08, 20 December 2008 (UTC)[reply]

I guess it could. Friction is only 18,104 bytes currently. Adding the non-reduncent meat of this article wouldn't make it too big. Wanna insert the merger proposal templates? -AndrewDressel (talk) 21:48, 20 December 2008 (UTC)[reply]

Done. Wizard191 (talk) 22:51, 20 December 2008 (UTC)[reply]

I definitely like the idea of eliminating redundancy. It's been bothering me for months. The hard work is in deciding which parts are better, and making them fit together. -- Another Stickler (talk) 00:23, 21 December 2008 (UTC)[reply]

One other thing. This article still needs to exist after the merge, even if only as a redirect, so as not to break the what-links-here articles' links, or the existing redirects: Friction coefficient, Friction coefficients, and Frictional coefficient. -- Another Stickler (talk) 02:20, 21 December 2008 (UTC)[reply]

That is standard practice when merging articles. The merger is also supposed to go back to all of the original redirects to this page and then direct them to the new page to eliminate double redirects. - Wizard191 (talk) 02:28, 21 December 2008

Here's another one: Friction angle. It's even more of a stub. -AndrewDressel (talk) 20:05, 21 December 2008 (UTC)[reply]

LOL...I just created that article. But you are completely right, that should be merged as well. Wizard191 (talk) 21:42, 21 December 2008 (UTC)[reply]

Done and done. -AndrewDressel (talk) 16:04, 25 December 2008 (UTC)[reply]