# How to measure stress/tension on a rope?

Pendulum, yes.
But length only, not weight. Therefore, probably no help here.
Perhaps if you knew the length and weight of the string, you could calculate the center of mass by the period of the swing, then from that the mass of the object.
But my last Physics class was about 30 years ago...
Rufus
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Tony Limson wrote:

Maybe you're trying to design the ultimate way to hang people? :D
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Tony Limson wrote:

I'm sure Gary Peek would know. He's an occasional poster on this group and has used our controllers to measure tension on parachute shrouds.
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I dont know the maths (too long ago when I did this sort of thing) but surely applying a force to the object that moves it a distance by a transducer then you can calculate the weight of the object - eg m=force x distance or something - then by measuring the period of the swing you can calculate the length of the string.rope and by using a lazer 'device' measure the diam of the rope/wire etc you can calculate it own weight (or close to it) - then the stress etc becomes the sum of the object plus the weight of the string
Or am I just rambling?
David - who loved physics but was hopeless at maths
Jim Stewart wrote:

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My company makes these
http://www.dqplus.com/rlt.htm
Eric
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snipped-for-privacy@abcde.com says...

Lots of people make load cells designed to measure tension on lines. One compact version---albeit for higher loads, is shown at:
http://www.atairaerospace.com/das/sensors /
Mark Borgerson
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a
string?
Piece of cake. Build a simulator, that is, an exact replica of the size or wire or string, the length, and fix one end of the string to an anchor, and the other end over a pulley with a weight on it. Now take a spring scale such as those used by fishermen and hook your stretched string in the middle. Have a piece of paper behind the line and mark the paper along the straight line. Now hook onto the middle of the string and apply pressure. Measure the distance in inches or centimeters, and write down the pull in pounds or grams at different distances. Now change the weight on the string and repeat the experiment. With this information in hand you can do a simple proportional formula extrapolation for the unknown in your actual case.
Let us know what happens since this seems to be a very interesting thread.
Wayne www.pueblaprotocol.com
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The tighter the rope the higher resonant frequency becomes like stretching an elastic band. It would require something to give it a twang and a microhone to pick up the resulting ringing.
----------------------------------------------------------------------- Ashley Clarke -------------------------------------------------------