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Assume a spherical horse moving through a vacuum... ;-)Unless the rope is infinitely rigid (wonderful first year physics assumption),
You might try calling the U.S. Navy NAWS, China Lake, Ca.(a) Imagine an 5-100kg (we do not know exact weight) object is hanged
with a
piece of string/rope/wire and swings randomly.
(b) We do not have access to either end of this string.
(c) How can we measure, electronically,em the stress/tension on the
string?
I think you need to say if you are allowed to cut the rope in order to
insert a transducer (load cell etc).
Also the question appears a bit homework-like! So if it isn't, perhaps
you should tell us a bit more about the application so that people are
not put off replying.
John Devereux
No, this is not homework, and I'm not a student.
Imagine a parachute. How can you measure stress/tension on a parachute line?
You can not access the either end of the string/line. (One end connectected
to parachute, the other is connected to carabiner.)
wire or string, the length, and fix one end of the string to an anchor, and(a) Imagine an 5-100kg (we do not know exact weight) object is hanged with
a
piece of string/rope/wire and swings randomly.
(b) We do not have access to either end of this string.
(c) How can we measure, electronically,em the stress/tension on the
string?
Piece of cake. Build a simulator, that is, an exact replica of the size or
Just to be pedantic, that's the oscillation period, not frequency.Dave Hansen wrote:
Umm, no. But thanks for playing.
Hint: where is the "weight" in 2*pi*sqrt(L/g)?
Try 2*pi*sqrt(L/g)= 2*pi*sqrt(m/k)
where m = mass
On Fri, 09 Sep 2005 18:14:21 +1000, Mark Harriss <billy@blartco.co.uk
put finger to keyboard and composed:
Dave Hansen wrote:
Umm, no. But thanks for playing.
Hint: where is the "weight" in 2*pi*sqrt(L/g)?
Try 2*pi*sqrt(L/g)= 2*pi*sqrt(m/k)
where m = mass
Just to be pedantic, that's the oscillation period, not frequency.
And "proportional" implies a linear relationship, not sqrt.
And the formula strictly only holds for a "simple" pendulum, ie one
where the oscillation angles are small.
See http://hyperphysics.phy-astr.gsu.edu/hbase/pendl.html
As for your interpretation of Hooke's Law, how long is a string when
no force is applied to it? ;-)
Hint #1: F = k.dL, not F = k.L.
See http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/SHM/HookesLaw.html
Hint #2: Would a 100kg mass swing with 10 times the period of a 1kg
mass, if released at the same angle?
-- Franc Zabkar
Please remove one 'i' from my address when replying by email.
I didn't bother to read all of this post, but if the answer seems obvious,I haven't seen all of this post, but the answer seems obvious.
The tighter the rope the higher resonant frequency becomes like stretching"Tony Limson" <tl@abcde.com> wrote in message
news:43203573$0$21677$afc38c87@news.optusnet.com.au...
(a) Imagine an 5-100kg (we do not know exact weight) object is hanged with
a
piece of string/rope/wire and swings randomly.
(b) We do not have access to either end of this string.
(c) How can we measure, electronically,em the stress/tension on the
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
Here's something that the OP may be interested in.(c) How can we measure, electronically,em the stress/tension on the string?
Study catenary curves. Apply some high school physics and algebra.
Tony Limson wrote:
(a) Imagine an 5-100kg (we do not know exact weight) object is hanged with a
piece of string/rope/wire and swings randomly.
(b) We do not have access to either end of this string.
(c) How can we measure, electronically,em the stress/tension on the string?
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.