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Author Topic: Sum of torque  (Read 173833 times)

EOW

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Re: Sum of torque
« Reply #105 on: January 03, 2015, 12:25:50 AM »
I tested on Algodoo for look at all angular velocities, it seems ok. I done a video :

https://www.youtube.com/watch?v=_zsx3ehhUto&feature=youtu.be

The stem move a little, the mass of the stem is very small, there is friction between the purple stem and red disks. The support has only an angular velocity at start, not disks.

Need the spiral for test the sum of the energy. The spiral is fixed and I think forces can be like I drawn.

The gif:

http://imageshack.com/a/img903/8053/6oVzC4.gif

And a bigger video:

http://youtu.be/TVv2GTwHhY0

The purple stem must block at the point B not A, because the distance move by the stem is not very big.
« Last Edit: January 03, 2015, 12:22:02 PM by EOW »

EOW

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Re: Sum of torque
« Reply #106 on: January 03, 2015, 12:48:41 PM »
I think the length travelled by the purple stem is not enough for reach the spiral. But I can fixe one part of the stem to the spiral, like forces F1 are always reported to the center of the support like I drawn, this could say the red disk accelerate counterclockwise. But at start, the red disk don't turn around itself, so this is an additionnal energy. The purple stem has no mass.

2 Cases:

1/ the length travelled by the stem is greater than the "step" of the spiral, in this case I can block the stem and red disk increase their angular velocity clockwise
2/ the lenght travelled by the stem is lower than the step of the spiral, in this case I can attach the stem to the spiral, red disks increase their angular velocity counterclockwise.

The support don't receive a torque in case 1 nor in case 2.

Cycle:

Accelerate more and more the support, but at start angular velocity of the red disk is 0. The purple stem will accelerate the red disk in the counterclockwise direction.

EOW

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Re: Sum of torque
« Reply #107 on: January 04, 2015, 01:45:31 AM »
Maybe instead of use a spiral I can use another circle with the center just aside just for a transcient analysis.

EOW

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Re: Sum of torque
« Reply #108 on: January 04, 2015, 02:21:17 PM »
I can unroll a roller chain from one disk to roll up to another disk. Red disks don't turns at start in the labo frame reference = turn counterclockwise in the support frame reference. Like I unroll and roll up the roller chain, the support don't receive a torque. But there is friction and red disks decelerate in the support frame reference = accelerate in the lab frame reference. Think with the same diameter for disks (think in 3D, disk can have depth). The roller chain has no mass (or as lower as possible). Disks can be very close from one to other like that the torque on the support is very small.

Cycle:

1/ Turn clockwise at w the support
2/ Unroll and roll up the roller chain from one disk to the other => win energy
3/ Decelerate the support and recover energy

I can repeat the cycle because the roller is roll up to the left disk. I need to change the position of the disk left <-> right only.

The friction can be asymmetric, no friction when I unroll and friction when I roll up or the other.

----------------------------------------------------------------------------------------

Or the idea with a pipe and a container of water, the idea is to move down the container with a higher weight from the volume of the pipe. There is air inside the pipe. For the shape of the reel : http://en.wikipedia.org/wiki/Spiral_of_Theodorus, like that the up force from the water to the pipe is always perpendicular to the trajectory, there is no torque on the reel from the force up.
« Last Edit: January 05, 2015, 12:38:21 AM by EOW »

EOW

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Re: Sum of torque
« Reply #109 on: January 05, 2015, 10:28:40 AM »
With 2 spiral of Theodore of Syrene, the force Fp from the water is gave to the spirals but this sort of spiral has Fp/2 at the center of rotation. I can full spirals with water inside, like that Fp = 0. I need energy for move up the water but that energy can be recover later.  I move up the water from the bottom spiral to the upper spiral and I move down the container full of water. Or move up the water only, but need to change the step of the spiral more and more lower when the diameter increase. With d1< d2 < d3 < d4 < d5 < d6.
« Last Edit: January 05, 2015, 01:58:30 PM by EOW »

dieter

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Re: Sum of torque
« Reply #110 on: January 05, 2015, 12:48:02 PM »
I think your creativity as well as your ability to imagine the devices in operation is remarkable. Genius at work I'd say.  :)
BR

EOW

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Re: Sum of torque
« Reply #111 on: January 05, 2015, 04:23:29 PM »
Thanks, but all my ideas are bad :(

I try with this new one, there is a big difference of radius of the left pulley and the right pulley, I try to move down a pipe with air inside. The bigger pulley decrease its diameter of x, and the small pulley increase its diamter of y with y >> x. If there is a torque this could say in the seond image the belt turn alone.

dieter

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Re: Sum of torque
« Reply #112 on: January 05, 2015, 05:09:22 PM »
You know, Edison used to say "I didn't fail, I have just found one more way the lightbulb does not work". So, work in progress is not bad only because it is not finished.


BR

EOW

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Re: Sum of torque
« Reply #113 on: January 05, 2015, 07:03:14 PM »
Thanks for your positive feedback !

The problem with the spiral is the torque on the pulley.

Maybe here, move to the right 3 objects in the same time, there is a force F to the triangle. The black is fully in water, it don't receive a left force.

EOW

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Re: Sum of torque
« Reply #114 on: January 07, 2015, 11:26:18 PM »
The support is turning clockwise at w. The disk don't turn in the lab frame referenceI => the disk is turning counterclockwise in the lab frame reference. I give the force F3 and I give the energy FRwt but I receive the energy 2FRwt if the diameter 'x' of the disk is small.  Like that, this work until the green disk is not at w.

It's possible to prevent the disk to turn: put inside the green disk a gyroscope, like that it's a continous movement.
« Last Edit: January 08, 2015, 09:24:30 AM by EOW »

dieter

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Re: Sum of torque
« Reply #115 on: January 08, 2015, 10:58:27 AM »
Instead of a gyroscope you could use a gear system. I did that once, with wooden gears  :) , it really worked, the non-rotation I mean. Like, when the green radius is 1 and the grey radius is 3 then there needs to be a second gear on the axle of the gray one, radius 1 and speed 2 times that of the grey.


BR

EOW

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Re: Sum of torque
« Reply #116 on: January 08, 2015, 05:59:57 PM »
You try to add gears to the device ?

I come back to the system with the spiral Maybe I can let a slope for the pipe and have Fp/2 on each reel with no torque.

EOW

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Re: Sum of torque
« Reply #117 on: January 11, 2015, 03:58:02 PM »
Wheels don't turn at start but like the support turns at w clockwise => wheels turn counterclowkwise at w. There is friction between wheels => forces F. Each wheel give a counterclockwise torque to the support, but instead to give that torque to the support I give it to each gyroscope: magenta forces. The gyroscope can cancel a part of this torque. It's necessary to take one force from other wheel and distribute to each gyrocopes. I think each wheel can have a gyroscope, like that, wheels don't turn even there there is a torque on it, like that each gyroscope keep its position like I drawn. I drawn 6 wheels but it can be more. Each gyroscope turn in a perpendicular axis when it receives a torque.

Friction give heating but it's possible to use an electromagnetic device for recover the energy.
« Last Edit: January 11, 2015, 06:18:14 PM by EOW »

dieter

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Re: Sum of torque
« Reply #118 on: January 11, 2015, 06:09:54 PM »
How do you handle the friction?


BR


EOW

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Re: Sum of torque
« Reply #119 on: January 11, 2015, 07:53:48 PM »
Friction is an energy => heating. When I calculated the sum of work, the energy won by the heating is lost by the support: it receives a counterclockwise torque, but here with gyroscopes, the torque to the support can be reduced. The friction can be replaced by an electromagnetic device and recover the energy to the electric energy instead of use heating. Like gyroscope are always in that position, they never rotate (they rotate in a perpendicular plan), it must be possible to recover more energy even while a short time.

Maybe I don't understand the word "handle", all wheels don't turn in the lab frame reference => turn counterclockwise in the support reference. Each wheel touch 2 wheels => forces F.