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Author Topic: Magnets, motion and measurement  (Read 168962 times)

Floor

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Re: Magnets, motion and measurement
« Reply #450 on: January 13, 2020, 07:14:40 PM »
Preparations for the next magnet interactions measurement set


                     floor

Floor

  • Guest
Re: Magnets, motion and measurement
« Reply #451 on: January 13, 2020, 07:20:45 PM »
Latest revisions of  two PDF files.

They help to answer the questions ...

what magnitude of force increments to use
                      and
how many measurements to make

when measuring the work / energy present in magnet interactions.

norman6538

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Re: Magnets, motion and measurement
« Reply #452 on: January 13, 2020, 09:07:01 PM »
WOW Floor. Very impressed and very anxious for the resulting numbers.
Norman

ayeaye

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Re: Magnets, motion and measurement
« Reply #453 on: January 15, 2020, 02:07:33 PM »
Floor,

Please add to your paper, if you measure force with a pulley and weight, there are two forces that can be measured at any point. One corresponds to the minimum weight with which the weight still doesn't go up, and the other to the maximum weight with which the weight still doesn't go down. The real force is the average of these two forces, and the static friction of everything, including the pulley, is the half of the difference between these forces.

This is not my idea, i think it is known already from ancient times. Like whenever one uses some balancing scales that are not perfect, and have some friction.


Floor

  • Guest
Re: Magnets, motion and measurement
« Reply #454 on: January 15, 2020, 08:52:00 PM »
Floor,

The real force is the average of these two forces, and the static friction of everything, including the pulley, is the half
of the difference between these forces.


Thank you eyeeye, good input.

This is already  my standard practice when doing measurements.  However, when measuring in the higher force area
of the curve I find it makes too minor of a difference to do so.   

1. I move the sliding unit BACKWARD (against the weight) a short distance from where it seems to have reached equilibrium between the weight and the magnetic force and then re-release it.

2. Then I move the sliding unit FORWARD (against the magnetic force) a short distance from where it seems to have reached  equilibrium between the weight and the magnetic force and then re-release it.

Although I find that if makes little or no measurable difference in the higher force range, it typically results in an average which is derived from +- 1 degree to as much as +- 2 degrees in the lower force ranges  ( "lower force range" is  <=  25 grams).

                 best wishes
                      floor

Floor

  • Guest
Re: Magnets, motion and measurement
« Reply #455 on: January 21, 2020, 07:45:42 PM »


                             https://www.youtube.com/watch?v=zWld721Wk-Q

                         floor

norman6538

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Re: Magnets, motion and measurement
« Reply #456 on: January 21, 2020, 11:06:01 PM »
Floor, the youtube is so out of character that I suspect that you got hacked.

I have recovered a bit but my wife was back in the hospital for 5 days and now things have settled down enough to get a few hours back at the bench. So if that keeps up I should have some test results in a few days. I am waiting for the shoe glue to dry because some times hot glue to metal lets go but shoe glue really holds well. I'm trying to get power from repelling magnets by extracting a piece of metal between them releasing the repel work out. Now its up to the measurements...

Norman

citfta

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Re: Magnets, motion and measurement
« Reply #457 on: January 22, 2020, 12:48:49 PM »
Hi Norman,


I am not familiar with shoe glue but I have found two glues that seem to work well for my projects.  The first is Locktite GO 2.  It is heat resistant and waterproof and very strong.  I have not been able to get anything apart I have glued with it.  Only use it if you are sure you don't want to ever take apart again whatever you glue.  I have destroyed several magnets I glued with it when I tried to take them apart to reuse them.


The second glue I use is Goop.  It makes a pretty strong glue joint for holding things in place.  It is hard to pull straight apart but a strong twisting action will allow it to come apart.  Also the residue is like rubber cement and can be rubbed off whatever it is on.  It also stays somewhat pliable after drying so is good for projects where you might need a little flexibility.


Glad to hear you are on the mend.  Hope your wife is soon back to normal also.


Take care,
Carroll

ayeaye

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Re: Magnets, motion and measurement
« Reply #458 on: January 22, 2020, 04:54:47 PM »
The shoe glue is just rubber cement. There are many such glues, but they are basically all the same, it's rubber in a solvent. When the solvent dries, what is left is rubber. It is strong enough for almost all purposes. Because it's rubber, it can also be later removed, but removing it is not that simple.


Floor

  • Guest
Re: Magnets, motion and measurement
« Reply #459 on: January 23, 2020, 10:11:18 PM »
@Norman6538

Keep getting stronger.
Stay chill.

   floor

Floor

  • Guest
Re: Magnets, motion and measurement
« Reply #460 on: February 12, 2020, 08:10:57 PM »
My test bench is set up, level and calibrated.   AT this point all that I am doing, are rough measurement sets and playing around with it ( just to warm up).

I still need to clean up / test the triple beam balance I recently acquired.  Thanks


In the interim I make this challenge to all readers....



                                                                                                                      CHALLENGE
         
In the method which I demonstrate, the output (by falling) work  is undone during each cycle, but, the input (by lifting) work is also undone during each cycle.  The output "work" is more than twice the input "work".

The operation you present, must be indefinitely cyclically repeatable. The use of levers and springs is permissible.  In short, demonstrate the cyclical lifting of a greater weight upon the long side of a lever by using a lesser weight upon the short side of that same lever or...... some other mechanically equivalent device which uses mechanical springs.

Mechanical output must exceed mechanical input in each cycle, even if  that mechanical output may be undone during each cycle (sums to zero). A mechanical spring or springs may be used in the device.  Remember however, the input mechanical "work" in each cycle, must always be less that the output mechanical "work" during that cycle.

            Meet or exceed the below, or at least exceed 1 to 1.
Cause 115 grams to be lifted 40 units of distance against gravity, by the lowering lowering of 100.75 grams 22 units of distance by gravity.
          In the exemplary demonstration I provide.......
The force ratio is 100.25 grams input to 115 grams output.
The mechanical displacement ratio is 22 units input to 40 units output.
                        The work in to work out ratio is....
      100.75g x 22 = 2216.5 input.   115g x 40 = 4600 output.
As I said (in my exemplary device), the work done both as the lifting and the falling is undone in each cycle.


        HERE @      https://www.dailymotion.com/video/x7b3x9a

   floor

ayeaye

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Re: Magnets, motion and measurement
« Reply #461 on: February 13, 2020, 10:15:20 AM »
I must say that i used matchboxes in my experiment, to put a big magnet under an angle vertically. The key is that there has to be three points of support, in such a way that when trying to move the upper corner of the magnet horizontally, there is enough resistance in both directions.


norman6538

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Re: Magnets, motion and measurement
« Reply #462 on: February 13, 2020, 01:52:51 PM »
Excellent workmanship Floor but I don't get this point. You said

"As I said (in my exemplary device), the work done both as the lifting and the falling is undone in each cycle."

To me the basic cycle pattern is
1. set the device into potential work out which requires some work in.
2. that work out is released and can be seen and measured.
3. reset the device so that 1-3 can be repeated  which requires some work in.

Please help me understand this a little more.
Thanks for all of your diligent work.
Norman


Floor

  • Guest
Re: Magnets, motion and measurement
« Reply #463 on: February 14, 2020, 11:44:30 PM »
@Norman6538

The device is sitting there..

          As in the video, starting position.

There is a 115 gram weight hanging from the rotating unit's pulley. 
That weight is in its HIGHEST POSITION (0 degrees of rotation on the rotating unit's scale).
Magnetic force between the two magnets, is holding it in that highest position.
This is because the force to cause the rotating magnet to rotate to the vertical and 0 degree position is is at its
maximum. 
This is because the rotating and the sliding magnets are nearly touching. 
The closer these two magnets are to one another the more force there is to cause that rotation.


!. INPUT .... Pushing upon the sliding action (with the finger) lifts the 105 grams 22 units of distance (via the pulley benieth the sliding unit).
Actually this is only 101.75 grams lifted, considering that there is a counter weight that pulls / keeps the thread
that connects the sliding unit to the sliding unit, scale dial pulley. 
The COUNTER WEIGHT thread wraps in the opposite direction on the sliding unit, scale dial pulley, and keeps the thread taught.
(opposite wrapping direction to the thread connecting the SLIDING UNIT to the sliding unit, scale dial pulley,
That counter weight is 4.25 grams  (105 g minus 4.25 grams =100.75 grams).

That pushing of the sliding unit, with the finger also separates the sliding magnet from the rotating magnet

2. Output # 1...  The weight upon the Rotating unit falls.
This is because the two magnets are now more distant from one another.
That weight is 115 grams and it falls 40 units of distance.
This output occurs at the SAME TIME as does the input from the finger push.

3. Output # 2 occurs as the force from the finger is released (the sliding unit weight falls to its original position).
This output occurs at the same time as does the lifting of the rotating magnet
(by magnetic force between the two magnets) as the falling of the weight benieth the
sliding unit draws the sliding unit magnet back toward the rotating unit magnet.

   best wishes
                floor

norman6538

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Re: Magnets, motion and measurement
« Reply #464 on: February 15, 2020, 02:40:44 AM »
Floor thanks for your explanation.
This is how I understand it now.

  UOW is units of work

1. push magnets together with 2216.5 UOW (100.75  grams 22 units distance)
    (105 g weight minus 4.25 grams =100.75 grams).

2. making  4200 UOW by twisting/rotating/lifting
    (105 grams lifted 40 units of distance)

3. release the sliding unit to reset itself (preloaded/balanced to pull back )
4. repeat step 1 using 2300 UOW from the jump start first step 1. above.

To make it a  self runner then lift 2 weights
1. 2300 UOW (57.5 g x 40 units) from the first step 1 above.
2. 1900 UOW (47.5 g x 40 units) totally extra for external use...

BUT  some of the 1900 UOW will have to be used for switching the weights
from lifted to using.....which I call switching.  That is the step that always snagged me.

Norman