Talk:Coefficient of friction

message: 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)
thread_title:  Confusion

message: 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)
replies: text: 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)
replies: text: 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)
thread_title:  Free body diagram 

message: 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)
replies: text: Clarifying - I mean ruthless deletion of redundant content, not of the article itself. Querl 06:41, 19 February 2007 (UTC)
thread_title: Duplicates duplicates

message: 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)
thread_title: Values?

message: 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)
thread_title:  German wikipedia 

message: 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)
thread_title:  Frequent Mistakes 

message: 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)
replies: text: 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)
replies: text: 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)
replies: text: 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)
replies: text: 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)
thread_title: resultant force

message: 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)
thread_title: normal friction possibly confusable with normal force