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dmitri said..

Macroscien said..

2 tendons connect bicep to the shoulder: the long one and the short one.
am waterstarting and getting pulled by 50 knts gust, one of the tendons is going to break.
Which one is it ?

Wish I didn't know the answer

I was guessing the short one. (I was wrong, I just googled it, and its normally the long one that tears!)

I just had shoulder repair surgery, and they were unsure if the bicep tendon had torn until they went in with the arthroscope. Luckily it seemed okay, but before I went in I researched it, and they screw the tendon to a different part of the humerus (I think), so you need to take it easy until the tendon has joined properly. I think this means almost no load on that arm for a while.

I think even on this forum there are past stories about people not getting it repaired. Some with no loss of strength and others with a loss of strength that wasn't really hinted at.

You are going to get it repaired right?

^^that was a few years back..no repair..the surgent I had appointment with told me..(when found out that I had no insurance) not to bother with repair and live with only the short one which is unbreakable due to its thickness.

cool little post macro. Thanks

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Poida said..
Structural engineering 101 - statics
where are the first year engineering students?

right line is under more tension

Dude, it's so obvious now I look at again : \

Exaggerate to see clearly, man.

If Nellie were like really, really hanging under the right-hand line, like it were practically pointing straight down, then practically all her weight would be under that end of the line.

[slaps forehead]

I think the confusion with this issue comes from one of whether the line is symmetrically hung or asymmetrically (like the one in the drawing). If asymmetrical then it is clear the right hand line is going to be taking more of the load.

Where I suspect confusion is arising is that, if symmetrical then the longer the line (and thus the more vertical the pull), the less will be the load on the line and its attachment points. The ropebook diagram from Clarence on the previous page is dealing with a symmetrical load.

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clarence said..

Each anchor point has a breaking load well above that of the clothesline; same knots at each end; we are talking about viewer's persepctive.

www.ropebook.com/information/vector-forces/

And... how do slack-liners/high-liners rig between two cliffs? What type of static (?) rope do they use?

I think this guy needed to look at dmitri's puzzle before taking off.

This is what happens when physicists or physics teachers (sorry, educators- no disrespect intended) ask the question.

Trick question, or imprecisely worded?

Or is the answer (d)- Neither.

Definition of verge - an edge or border, an extreme limit beyond which something specified will happen.

The question doesn't say the line will break, just that it is on the verge of breaking. It isn't clear whether it is on the verge relative to time (it will break, it's just a matter of time) or tensile strength (it will hold for the moment, but it anything increases, it will break).

If Nellie hangs motionless, and there are no other forces acting on her to increase the tension on the lines, and the lines aren't actually deteriorating, then in the static state, the lines will support her weight. Neither is more likely to break than the other if nothing else changes. If the tensile (breaking) strength of the line is uniform along its length, that part of the line on the right of the picture is under greater tension, and would be closer to its breaking limit. But as long as both parts of the line are subjected to less that their tensile (breaking) strength, and nothing else changes, neither is more likely to break than the other. If the force exerted by Nellie increased, i.e if Nellie Newton somehow increases the number of Newtons she is exerting on the lines e.g. if she increased her mass (by eating several hundred passing butterflies) or was buffeted by a gust of wind resulting in an increased load on the lines, the line on the right of the picture is more likely to break .

And as first pointed out by Subsonic, if the verge refers to time, not tensile strength, the answer could equally be (a) Left side (Nellie's left), or (b) Right side (viewer's right).

FFS, ask the right F'n question.

yep just what I though lol