re: energy producing experiments

[Kator01]

thank you Tarsier

good demonstration .


Levins last sentence..not payed attention to:


https://youtu.be/lvfzdibrUFA?t=817


I emphasize this because he made the same remark in a electro-physics lecture of induction. Induction very much resembles inertia.


I have to say that I am very grateful to Delburts effort of showing the Cyl. & Spheres system. It certainly was not easy to
analyse the NASA Despin correctly and do all the video-demonstration years ago.
This Cyl. & Spheres System is extraordinary and has a embedded working principle which is not easy to detect/ understand  and demonstrates that
energy is not conserved. It contains this plus-element NASA was hiding by blasting away the steel-balls at the most interesting point in time concealing the kinetic engergy of the balls


The lever-system is conventional physics and only shows energy-conservation.


The whip-System is another one I regard as suspicious but hard to repeat without complex measurement-equipment.


I myself concentrate my efforts on Cyl & Sphere System.




Mike

[Tarsier_79]

The cylinder and spheres is interesting. I have not looked at it in depth for a long time. IMO a better experiment needs to be done. I have not had the time or motivation yet to do one., and I have not seen one done the way I want to see one.

I would like to to see a measured input, a calculated kinetic total energy, a complete despin,  where the balls are released and their exit KE measured through distance traveled. Not an easy task to successfully test and accurately measure each step. For me it would be ideally on a fixed axle.

I look forward to seeing your tests.

[Delburt Phend]

A Beautiful and Engaging Investigation of Angular Motion! | Rotational Inertia Demonstrator - YouTube  This difference is not so monstrous     8.4 sec to 3.4 sec for an acceleration difference  of 1 to 6.1, which looks very close.

The closer you are to just overcoming the friction; the more friction affects the experiment. The slower the rotation or lower the rotational force, the greater the percent bearing friction plays upon the system. The friction can be significant.

You could conduct the experiment at the same rotational speed; and in that why frictional differences drop out. Such as placing 1/3 the mass at three times the distance. You can accelerate 1/3 the mass at 3 times the distance and it will rotate at the same rate. 

You both ignored the negation of your math. The radii ratio of the small 'torque' pulley and the near inertia position can equal the radii ratio of the large pulley to the long inertia position.

But when you move from the small inertia position (15 cm) to 3 times that radius; then the inertia for r² is 9 times as great.  You can multiply the force by moving the applied torque to the large radius pulley position but that only gets you to three times harder to move.

Let put this in an algebraic description: the small pulley is 2 cm and the large pulley is 6 cm. the small inertia position is at 15 cm on the rod and the large is at 45 cm.

You start with 2 cm / 15 cm 'torque over inertia' and end with 6 cm / 45 cm 'torque over inertia'. But your r² says that 6 / 45 is three times harder to move than 2/ 15. This is impossible because they are the same numerical relationship between force and mass. This is a fatal math error, you can not brush this aside.

If you put the mass at 5 cm it allegedly would be 9 times easier to move; and you could move the applied torque to 2/3 cm. It would still be 3 times easier to move but you are back at the original ratios of radii. This 2/3 cm / 5 cm  should not accelerate 3 times faster:  2/3 cm / 5 cm, 2 cm / 15 cm, and 6 cm / 45 cm should all have the same acceleration.

Tarsier quote: 1 newton meter of torque is 1 newton of force at 1 meter, or its equivalent regardless of the radius it is applied. 2 newtons at 1/2 meter etc. It doesn't care if there is very little resistance or very much.


'It doesn't care if there is very little resistance or very much."


This simply is not true; If you are tightening a lug nut and it is moving freely, the torque wrench reads zero. Only when the nut tightens against the rim is any torque applied. And the resistance always equals the torque. 

[Tarsier_79]

The radii ratio of the small 'torque' pulley and the near inertia position can equal the radii ratio of the large pulley to the long inertia position.

That is a good point. It is a pity that wasn't shown.

This simply is not true; If you are tightening a lug nut and it is moving freely, the torque wrench reads zero. Only when the nut tightens against the rim is any torque applied. And the resistance always equals the torque. 

If a constant torque is applied to a free spinning nut, it will spin very fast. Like what happens to a wheel nut with a pneumatic hammer drill.

[Delburt Phend]

You have a one meter low mass tube that has 2 kg attached to one end and 5 kg attached at 30 cm from the other end. The tube is moving sideways at 3 m/sec so that both the 2 kg and 5 kg masses are moving at the same speed (3 m/sec). 

The tube is caught on the end near the 5 kg. The tube's end is then on a bearing and the tube is forced to rotate. The 5 kg now has a 30 cm radius, and the 2 kg has a 100 cm radius.

Where is the center of mass and what is its speed?