re: energy producing experiments

[Delburt Phend]

I took a video of a 2.5 kilogram cart wheel that can be stopped by two 152 gram spheres. I tried to post it on line but YouTube said the app was temporarily closed.

This cart wheel would be the same basic experiment as the cylinder and spheres (see Delburt Phend; you tube). The mass ration is about 9 to 1. This means that when the spheres have all the motion they have nine times as much energy.  ½ *.305 kg * 9 m/sec  * 9 m/sec = 12.35 joules; ½ * 2.745 kg *1 m/sec * 1 m/sec = 1.37 joules:   momentum is conserved; .305 * 9 roughly equals 2.8 *1 

The wheel is roughly the same shape as the gyroscope. And the interesting thing is that the energy transfer to the spheres only takes about one third rotation. Experiments have shown that the stop occurs in the same quantity of rotation no matter what the rate of rotation. The quantity of friction in one third rotation must be very small. So you have a huge quantity of energy produced with very little friction and in very little time.

[Delburt Phend]

There should be a very simple experiment on the internet: but I could not find it. He experiment would be a puck, on a frictionless plane, rotating on the end of a string; and then the string comes in contact with an immovable pin. The puck then begins rotating about the immovable pin. Lets say the string length is originally 50 cm; and then after it begin rotating about the pin it has a 10 cm string length. So we have a puck rotating at 50 cm and then at 10 cm.

When we burn through a string that is rotating a puck; the puck will move in a straight line with the same speed as it was moving around the arc of the circle. Therefore we also know that the speed around the smaller 10 cm circle will be the same as the speed of the puck in the 50 cm circle.

Just to get real numbers lets say that the puck has a mass of 80 grams and the speed is 3 m/sec.

So in the large circle the energy is: ½ .080 kg * 3m/sec * 3/sec =  .36 joules

In the 10 cm circle the energy is: ½ .080 kg * 3m/sec * 3/sec =  .36 joules

The linear momentum in both circles is: .080 kg * 3 m/sec =  .24

But what about angular momentum conservation?  The angular momentum is L = R * linear momentum.

The angular momentum of the .5 meter circle is: .5 m * .24 = .12

The angular momentum of the .1 meter circle is: .024

So the angular momentum of the system is not conserved.

Shouldn't you be skeptical of all those high school teachers and college professors that told you something that is false.

Angular momentum is not a conserved quantity. Some lecturers will actually tell you that linear momentum changes so that angular momentum can be conserved. These are the people that never back up their conjectures with experiments.

[Delburt Phend]

https://www.youtube.com/watch?v=AzgasHgVOy8   

The experimenter cuts the string and the momentum is then equal to the linear momentum (velocity * mass) that the puck had while traveling around the arc of the circle.

It doesn't make any difference what length of string the experimenter used, he could have used any length that fits the table.  That would of course be an infinite number of lengths for R; the radius. This infinite number of Rs would give you an infinite number of angular momentums: because angular momentum is linear momentum times R.

Further: the experimenter could reattach the puck to a different length of string. That would give you the same linear momentum on a different length of string. That would give you a different angular momentum. Obviously angular momentum is not a conserved quantity. 

So what else did all those high school teachers and professors tell you that was false. 

[conradelektro]

You might want to read that:

https://courses.lumenlearning.com/boundless-physics/chapter/conservation-of-angular-momentum/

Give yourself the time to understand. Your high school teacher was not such a bad guy.

Greetings, Conrad

[Delburt Phend]

They use the ice skater because there are no real experiments that prove that angular momentum is conserved. There is no way to quantitatively evaluate (at least not in high school, or at most universities) the mass of an ice skater or someone seated on a spinning chair. 

Use a pincher to hold the string instead of a scissor, and the puck will proceed with the same arc motion in a smaller circle. Angular momentum is not conserved: but it is used to cover for their other false concepts.

Linear momentum is conserved in rotation. Not all lines are straight.