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#2240 by Gilbertdrive on 11 May, 2016 17:00
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You're welcome. Since I really don't know him, its best I not push him for more answers. For whatever reason, his reply is what it is. I certainly would think he accepts email inquiries on his website. Its possible you could receive more info that I did.Its probably the most we can expect from Mr Shawyer. I'm sure our questions have been asked and re-asked many times. I have not followed him over the years like many have, so I have no particular interest in gaining more information from him. Quite frankly, it was Iulian Berka that launched me into the emdrive world when he used to post here before moving to China.
So, do not take account of my last message. I perfectly understand if you prefer to stop the exchange for now with Roger Shawyer
Thanks very much to have send him the last one !
You are right. Thanks for the information. Maybe I shall try it later, if I dare
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#2241 by rfmwguy on 11 May, 2016 17:05
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Here's where it gets difficult. The torsion wire test has a limitation...total mass. Having studied piano and related wire more than I care to, there are limits as to how many pounds of free weight you can hang on them. I think Yang had to use a 3 wire suspension system. Batteries are notoriously bulky and prone to outgassing or heating under load (center of mass change?). Neither one is good. Secondly, batteries need an inverter if a magnetron is used...not so for lower powered Solid State sources in the 30 Watt range or slightly above...but 900 Watts? Uhhh, not easy with batteries.
A perpendicular power injection to the center of the torsion beam COULD push or pull the beam at the connection point whether by thermal deformation or some other form of force(?). THAT is easy to measure...LDS the injection point on the beam and look for the perpendicular force when the drive is pointed up or down, not horizontally.
If I play devils advocate, I've been around high power RF transmissions systems for the better part of my career and never observed an instantaneous kinetic force on transmission lines when power was applied. However, I did observe through repeated heating and cooling cycles, connectors (mainly the outer shell) fail at the coax connection. Personal observations are simply that, personal observations. We will need to eliminate potential errors provided the error potential has some documented experiment which highlight it. New error theories may not be worth chasing (IMHO only).
Anyway, the best thing to do is to do both test With external supply, and with batteries.
It will help to quantify the possible coax influence.
A very funny solution would be... if the Emdrive was finally not working, but if a long coaxial cable, with the appropriaté parameters, was a real propellantless device.
I guess those who say they would reject data from all off-board power systems would need to be very explicit in the objection, down to quantified data regarding the error it could create on a center-fed torsion test. Coaxial momentum beyond Lorentz and thermal distortion? Yeah, a new propulsion system
I might have to start a new thread on that one...not.
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#2242 by Rodal on 11 May, 2016 17:08
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This was not a case of NSF pushing Shawyer for answers, on the contrary.
You're welcome. Since I really don't know him, its best I not push him for more answers. For whatever reason, his reply is what it is. I certainly would think he accepts email inquiries on his website. Its possible you could receive more info that I did.Its probably the most we can expect from Mr Shawyer. I'm sure our questions have been asked and re-asked many times. I have not followed him over the years like many have, so I have no particular interest in gaining more information from him. Quite frankly, it was Iulian Berka that launched me into the emdrive world when he used to post here before moving to China.
So, do not take account of my last message. I perfectly understand if you prefer to stop the exchange for now with Roger Shawyer
Thanks very much to have send him the last one !
NSF is a public forum: like a conversation taking place between people sitting at tables in a Cafe'.
There are conversations going on while suddenly Dave says: here is this presentation by Mr. Shawyer who does not want to speak to you directly but just want you to see his presentation saying that what you people are discussing is "Basic Science", basic science that you learned at school: you know: Newton, Maxwell and Special Relativity: all undergraduate stuff, stuff that has been around for over 100 years.
Mr. Shawyer here says that what you people are discussing: Quantum Vacuum, General Relativity, Unruh effect, McCulloch's theory, etc., IS NOT NEEDED, you are wasting your time: all you need is Basic Science, capisce ?
So this "Basic Science" by Shawyer was pushed on the NSF audience, not the other way around. Fine.
Then the people at NSF seriously address this "Basic Science" presentation, and distill their questions to a single precise question:
Mr. Shawyer, since you say that you are using Special Relativity to explain the EM Drive: how can you use Kinetic Energy to explain energy conservation? doesn't that contradict your claimed used of Special Relativity? To use Kinetic Energy, one would need a reference. What is that reference for Kinetic Energy for an EM Drive in outer space with no mass or energy spewing out of it, and under no action from external fields?
And the answer from Shawyer is: my equations have been approved by many "professional scientists", OK ? -
#2243 by rfmwguy on 11 May, 2016 17:13
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No offense Dr Rodal, but it appears you have already made up your mind about Mr Shawyer and I suppose I would not bother to answer this forum at all if I was him. Can't say that I really blame him...and I don't know him at all.
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#2244 by Rodal on 11 May, 2016 17:19
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No offense Dr Rodal, but it appears you have already made up your mind about Mr Shawyer and I suppose I would not bother to answer this forum at all if I was him. Can't say that I really blame him...and I don't know him at all.
I find it objectionable that you make remarks like this. Let me just leave it at that. -
#2245 by Gilbertdrive on 11 May, 2016 17:34
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Of course a space mission designer can't rely on circular reasoning like "Energy is conserved because Q decreases. Q decreases in such a way that energy is conserved", especially when energy is so ill defined to start with. So not only we are left to connect the dots and escape the circular reasoning by ourselves, but by Shawyers own indications one of the dots is fatally ill defined. At some point how Q is supposed to decrease must be stated in clear predictive terms as an explicit function of trajectory/use, because thrust must be known in clear terms for mission design.
It is the fact that Kinetic energy is not defined at all (because no referential) that makes this definition... undefined !
A definition of this type, but with a defined referential, could be used, for example, to calculate the acceleration of a car. If I know the power of my car, if it has the same efficiency at different speeds, and that I take the road for referential, I can legitimately use the Conservation of Energy principle to calculate the acceleration of the car. The buyer of the car will not tell me :
Oh, I have seen in your speed documentation that you uses CoE, so you are not technically proving that your car is respecting it. Maybe your car creates free energy. I can not caution that, and I will buy elsewhere 
But the problem with Shawyer is that, with standard physics, we have no way of finding a referential to applicate his formula without arriving to nonsense conclusions...
As Dr Rodal said, the most likely is that Shawyer has no referential to give... -
#2246 by rfmwguy on 11 May, 2016 17:35
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NSF-1701A Update -
So...torsion wire test stand. Weakness other than mass limitation appears to be return to center after rotational displacement and/or time. Think someone else mentioned this on the thread some time ago. Far more "stickiness" than I saw on the teeter-totter beam. Here's my thoughts on this since I observed it for myself:
Temperature...any temperature change in the torsion wire itself (I'm using 0.030) will cause this.
Mechanical termination...its best to use a wire clamp that is exposed directly at the drop point, not going through a hole or other guide which may cause friction slip. The very end of the clamp (beginning of the wire drop) needs to have the tightest grip. Same applies to the terminated drop.
I will re-do the top clamp assembly tonight and plan to watch for centering changes. In fact, I might try calibrating it with temperature if I have enough motivation...no promises
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#2247 by zen-in on 11 May, 2016 17:40
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In my setup where I'm feeding the frustum with a coax only where do you see it contributing to the anomaly?
The only action I have is the coax, the rest is in a sealed box and yes I'll cool the box with fans but the frame will have a plastic over the top of wire mesh Faraday shield.
...
Sorry for the crude drawings but they get my ideas across.
Shell
The largest source of error I would predict from that setup is the stiffness of the coax. The resting postion of the torque pendulum will be influenced by the coax. RF power sent through the coax will make it stiffer and there will be heating effects that will make the coax bend in one direction or another. I have done similar experiments where I used what seemed like flexible wire. As soon as power was applied the wires heated and started moving. -
#2248 by Gilbertdrive on 11 May, 2016 17:45
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In my setup where I'm feeding the frustum with a coax only where do you see it contributing to the anomaly?
The only action I have is the coax, the rest is in a sealed box and yes I'll cool the box with fans but the frame will have a plastic over the top of wire mesh Faraday shield.
...
Sorry for the crude drawings but they get my ideas across.
Shell
The largest source of error I would predict from that setup is the stiffness of the coax. The resting postion of the torque pendulum will be influenced by the coax. RF power sent through the coax will make it stiffer and there will be heating effects that will make the coax bend in one direction or another. I have done similar experiments where I used what seemed like flexible wire. As soon as power was applied the wires heated and started moving.
To have an idea, maybe you can try (with no Power On) to pull, or push manually on the cable, and see if there is no rotation at all of the emdrive ? -
#2249 by SeeShells on 11 May, 2016 18:20
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...
In my setup where I'm feeding the frustum with a coax only where do you see it contributing to the anomaly?
The only action I have is the coax, the rest is in a sealed box and yes I'll cool the box with fans but the frame will have a plastic over the top of wire mesh Faraday shield.
...
Sorry for the crude drawings but they get my ideas across.
Shell
The largest source of error I would predict from that setup is the stiffness of the coax. The resting postion of the torque pendulum will be influenced by the coax. RF power sent through the coax will make it stiffer and there will be heating effects that will make the coax bend in one direction or another. I have done similar experiments where I used what seemed like flexible wire. As soon as power was applied the wires heated and started moving.
To have an idea, maybe you can try (with no Power On) to pull, or push manually on the cable, and see if there is no rotation at all of the emdrive ?
Yes. I'm planning to set the digital scales up on a slide with a lead screw and slowly move the scales into the beam. That will tell me the amount that's needed for deflection.
Shell -
#2250 by zellerium on 11 May, 2016 18:28
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In my opinion the discussion with and about Mr. Shawyer has been beaten to death. It doesn't seem like there is anything more to gain from such discourse.
However it's exciting to see all the updates from other builders! I've been considering building a piano wire torsion pendulum when I have time, but for now I'm working on addressing the movement of my classical pendulum. The plots shown below are 5 consective test runs from yesterday at full microwave power after the shown VNA plot was locked. There are several important things to note:
1. During the first test the x axis deflection surpassed the boundaries set on the oscilloscope, hence the 'planteau'.
2. The time in between tests was approximately 50 seconds which was not enough time for the pendulum to return to its starting position which can be seen from the y axis drift between plots.
3. I have not performed calibration deflections for the x-axis, although clearly the x axis delfection is much larger.
The y axis deflection is between .2 an .5 mm corresponding to 5~15 mN judging by the calibration plot. The y axis delfection indicates the pendulum is swinging forward (toward to dielectric) and the x delfection indicates it is torqing clockwise if looking from above (with the laser coming from the top).
In other words, the reflected laser point is moving into page and vertically if looking at the test-setup picture.
4. The calibration plot was created using three different weights on a pulley and averaging the measured deflection of 5 tests each. I should go back and do some statistical analysis on how close each of these were but for now there are other pressing matters.
5. After removing the magnetron and replacing the professionally calibrated magnetron antenna, the resonance plot was essentially the same. The observed resonance appears to be much much more stable with the new VNA. The cavity seems to be more resilient to drift, sporadic jumps, and remails on resonance even directly after testing.
Tomorrow I'm planning to try different wire orientations, if anyone has any suggestions I'm happy to hear them.
[I'll be in class and mostly unavailable until after 8 pm tonight unfortunately]
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#2251 by rfmwguy on 11 May, 2016 19:25
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Way to go Kurt!
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#2252 by rfmwguy on 11 May, 2016 19:53
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***Science Writers Alert***
(On second thought, a young South African student designing, building and demonstrating the EMDrive and winning a trip to the USA this week and being eligible for a share in $4 Million Prize Money is a pretty cool press release).
Good Luck to Paul from South Africa this week in Phoenix at the Intel International Science and Engineering Fair (Intel ISEF 2016)!
"Name: Paul Stansell
Location: Johannesburg, South Africa
School Represented: Sacred Heart College
Student Showcase: Electric Space Propulsion – An Exploration into Innovative Propellant Solutions Involving the Testing of an Electromagnetic Drive
Study Synopses: Since its birth, spaceflight has always been hindered by propellant constraints. Unfeasible amounts of fuel are required to cover the vast distances between stars and so modern spaceflight is confined to the solar system. A revolutionary electric propulsion system, according to Stansell, composed of a hollow asymmetric resonant cavity excited by microwaves, known as the EMDrive has been shown to produce a unidirectional acceleration although results have been inconclusive. This warrants further research.
According to Stansell a non-resonant EMDrive was constructed to act as a control, this design was then extended to create a new cavity which allowed for resonance at a frequency of 2450 MHz. The designs were tested in both the upright and inverted orientations to allow for EMDrive force separation from buoyant forces. The designs were tested on a millinewton resolution knife-edge fulcrum which was calibrated to accurately determine thrust magnitude.
Stansell revealed that due to thermal currents caused by the heating of the magnetron and cavity, each test experienced net upwards motion. However the resonant upright cavity moved upwards considerably more than the non-resonant control suggesting another force was at work pushing the cavity upwards. Additionally the resonant inverted test moved upwards considerably less than the control again indicating another force was counteracting the net upwards motion. This force varied in magnitude from 8.8825 millinewtons 11.8436 millinewtons.
In conclusion, according to Stansell, despite thermal current interference a replicable, anomalous thrust was produced. As the observed thrust is not yet attributable to any known physical phenomenon more research in vacuum is required."
(snip)
The final Intel ISEF 2016 winners will be announced, by Intel, during the course of the week.
http://www.itnewsafrica.com/2016/05/africa-has-strong-showing-at-intel-isef-2016/
More from: https://student.societyforscience.org/intel-isef
About Intel ISEF
The Intel International Science and Engineering Fair (Intel ISEF), a program of Society for Science & the Public (SSP), is the world’s largest international pre-college science competition.
Approximately 1,700 high school students from over 75 countries, regions, and territories are awarded the opportunity to showcase their independent research and compete for approximately $4 million in prizes.
Today, millions of students worldwide compete each year in local and school-sponsored science fairs; the winners of these events go on to participate in SSP-affiliated regional and state fairs from which the best win the opportunity to attend Intel ISEF.
Intel ISEF unites these top young scientific minds, showcasing their talents on an international stage, where doctoral level scientists review and judge their work.
SSP partners with Intel—along with dozens of other corporate, academic, government and science-focused sponsors—who provide the support and awards for Intel ISEF.
Intel ISEF is hosted each year in a different city (Los Angeles, Pittsburgh and Phoenix through 2019). The Local Arrangements Committees from each city partner with SSP and Intel to provide support for the event including the recruitment of 100s of volunteers and judges and in organizing an education outreach day in which more than 3,000 middle and high school students visit.
UPCOMING DATES AND LOCATIONS FOR INTEL ISEF
Phoenix, Arizona, May 8-13, 2016
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#2253 by aero on 11 May, 2016 20:48
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In my opinion the discussion with and about Mr. Shawyer has been beaten to death. It doesn't seem like there is anything more to gain from such discourse.
However it's exciting to see all the updates from other builders! I've been considering building a piano wire torsion pendulum when I have time, but for now I'm working on addressing the movement of my classical pendulum. The plots shown below are 5 consective test runs from yesterday at full microwave power after the shown VNA plot was locked. There are several important things to note:
1. During the first test the x axis deflection surpassed the boundaries set on the oscilloscope, hence the 'planteau'.
2. The time in between tests was approximately 50 seconds which was not enough time for the pendulum to return to its starting position which can be seen from the y axis drift between plots.
3. I have not performed calibration deflections for the x-axis, although clearly the x axis delfection is much larger.
The y axis deflection is between .2 an .5 mm corresponding to 5~15 mN judging by the calibration plot. The y axis delfection indicates the pendulum is swinging forward (toward to dielectric) and the x delfection indicates it is torqing clockwise if looking from above (with the laser coming from the top).
In other words, the reflected laser point is moving into page and vertically if looking at the test-setup picture.
4. The calibration plot was created using three different weights on a pulley and averaging the measured deflection of 5 tests each. I should go back and do some statistical analysis on how close each of these were but for now there are other pressing matters.
5. After removing the magnetron and replacing the professionally calibrated magnetron antenna, the resonance plot was essentially the same. The observed resonance appears to be much much more stable with the new VNA. The cavity seems to be more resilient to drift, sporadic jumps, and remails on resonance even directly after testing.
Tomorrow I'm planning to try different wire orientations, if anyone has any suggestions I'm happy to hear them.
[I'll be in class and mostly unavailable until after 8 pm tonight unfortunately]
Kurt - Good on you!
I'd like to know how you define your coordinate system. x, y, z with z being the axis of rotation is traditional.
You didn't give data for the z-axis, so I wonder which axis is the axis of rotation?
aero -
#2254 by keithpickering on 11 May, 2016 21:24
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4. The calibration plot was created using three different weights on a pulley and averaging the measured deflection of 5 tests each. I should go back and do some statistical analysis on how close each of these were but for now there are other pressing matters.
...
Tomorrow I'm planning to try different wire orientations, if anyone has any suggestions I'm happy to hear them.
[I'll be in class and mostly unavailable until after 8 pm tonight unfortunately]
The problem I see is that at low deflections, the force vs. deflection graph should be very nearly linear for a perfect pendulum, and only bend to any significant degree when deflections are quite large. (and then, it should be concave downward.) I assume that there is an unplotted point at 0,0 -- or am I wrong in that?
In any case, given that your pendulum is far from perfect, I would dearly like to see a lot more datapoints in the deflection graph.
Also, it's rather apparent from your test runs that there is quite a bit of hysteresis in the pendulum system, which (one would have thought) could or should have been captured in the deflection graph. So perhaps next time, instead of averaging five runs at every force, we could see each individual deflection (and bounce-back return deflections under zero force)? -
#2255 by Oakey on 11 May, 2016 21:56
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Hi All,
In Shells set up could magnetic bearings be used to anchor the piano wire top and bottom? If feasible it may show acceleration with a battery test without need to measure deflections?
Sorry just a thought. -
#2256 by Vesc on 11 May, 2016 22:02
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Quote
with a cute actuated robotic cradle that captures and secures the self contained assembly each time, and releasing before next test, and aligning and damping to rest position for a quick start again while we are at it.
mmh, just my idea if I had lot of spare time and a seriously oversized DIY budget to spend
( or needed to write a screenplay scene of a futuristic EMdrive lab, adding steam, lot of steam
)
If I had a huge budget to blow I'd encase the experiment in two hemispheres of YBaCuO2 soaked in Liquid N on the outside and rely on the Meissner Effect to eliminate the static field. Outside of that would be my Faraday cage. Then of course you have to run cabling through the hemispheres to get at the experiment. Hmm. Helmholtz Coils don't sound nearly so bad in comparison.
Here's a retro picture of a 3D arrangement of Helmholtz Coils used to cancel out the Earth's magnetic field (credit Wikipedia).
So how would you test such an arrangement? Stick a magnetic compass in the middle and see if you can get the needle to point in arbitrary directions?
Perhaps sometimes it's better to just live with an effect by taking careful measurements and calibrations. -
#2257 by Rodal on 11 May, 2016 22:24
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4. The calibration plot was created using three different weights on a pulley and averaging the measured deflection of 5 tests each. I should go back and do some statistical analysis on how close each of these were but for now there are other pressing matters.
...
Tomorrow I'm planning to try different wire orientations, if anyone has any suggestions I'm happy to hear them.
[I'll be in class and mostly unavailable until after 8 pm tonight unfortunately]
The problem I see is that at low deflections, the force vs. deflection graph should be very nearly linear for a perfect pendulum, and only bend to any significant degree when deflections are quite large. (and then, it should be concave downward.) I assume that there is an unplotted point at 0,0 -- or am I wrong in that?
In any case, given that your pendulum is far from perfect, I would dearly like to see a lot more datapoints in the deflection graph.
Also, it's rather apparent from your test runs that there is quite a bit of hysteresis in the pendulum system, which (one would have thought) could or should have been captured in the deflection graph. So perhaps next time, instead of averaging five runs at every force, we could see the actual deflections (and bounce-back return deflections under zero force)?
1) I think that Zellerium is measuring a torque with his pulley calibration. The restoring torque for a pendulum is:
Torque = m g L Sin[θ]
where:
m is the mass of the body
L is the distance from the pivot to the center of mass of the pendulum
θ is the angle from the vertical
which when we expand in a Taylor series is:
Torque = m g L (θ - θ3/3! +...)
which is a softening spring, as shown by Zellerium, in agreement with Zellerium's graph.
(The tangent of the torque vs. angle curve decreases for increasing angle: it takes less torque at higher angles)
I would plot instead the Force in the vertical scale and Displacement in the horizontal scale, as it is the usual convention to plot force vs. displacement (in springs, or in stress vs strain in materials), which would show a softening spring (since the force vs displacement curve has a decreasing stiffness slope at higher forces).
Secant stiffness: F/δ
Tangent stiffness: dF/dδ
F=Force
δ=displacement
2) Yes, in the calibration plot, more points are needed between 15 and 35 mN, as the "nonlinearity" seems to be mainly due to the last single point near 32 mN.
The torque vs. angle should be approximately linear up to 20 degrees or so. Maybe the nonlinearity is an experimental artifact???
Could use Excel to also plot the least square regression line fit going through the measured points.
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#2258 by Vesc on 11 May, 2016 22:57
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In my opinion the discussion with and about Mr. Shawyer has been beaten to death. It doesn't seem like there is anything more to gain from such discourse.
However it's exciting to see all the updates from other builders! I've been considering building a piano wire torsion pendulum when I have time, but for now I'm working on addressing the movement of my classical pendulum. The plots shown below are 5 consective test runs from yesterday at full microwave power after the shown VNA plot was locked. There are several important things to note:
1. During the first test the x axis deflection surpassed the boundaries set on the oscilloscope, hence the 'planteau'.
2. The time in between tests was approximately 50 seconds which was not enough time for the pendulum to return to its starting position which can be seen from the y axis drift between plots.
[snip]
Tomorrow I'm planning to try different wire orientations, if anyone has any suggestions I'm happy to hear them.
[I'll be in class and mostly unavailable until after 8 pm tonight unfortunately]
This behavior is making me wonder about thermal effects. Now that you have a good stable VNA. Have you tried runs off frequency? At say 2450MHz? Is that possible with your setup?
Dave
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#2259 by frobnicat on 11 May, 2016 23:10
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.../...
2) Yes, in the calibration plot, more points are needed between 15 and 35 mN, as the "nonlinearity" seems to be mainly due to the last single point near 32 mN.
The torque vs. angle should be approximately linear up to 20 degrees or so. Maybe the nonlinearity is an experimental artifact???
.../...
Yes for such small displacement pendulum should be close enough to linear. Maybe an artifact from the use of pulley ? If I understand correctly the calibrations weights are "redirected" to horizontal force ? Pulley is not that good for small forces : friction (dry friction ?) at the axis could explain the apparent "softening" for larger forces... also if it is dry friction it should be apparent as hysteresis. Most simple test : approach the equilibrium point by releasing (manually, smoothly) a calibration weight by above equilibrium or by below equilibrium, is there a significant difference in the rest position ?
edit: I mean, when the calibration weight is in place, approach equilibrium (manually, slowly, smoothly) by releasing the pendulum from left or from right deviation. Anyway, check for any difference when last rotation of pulley (before stable equilibrium) was clockwise vs anticlockwise.
I might have to start a new thread on that one...not.
)