re: energy producing experiments

[sm0ky2]

Well yes it is exactly like you say
Except for the part about the mass
And the string
And the momentum
25kg moving at 2m/s is going almost straight down
Not up. It will not be moving fast enough to put tension
On the string of 25 meters long
In the earths gravitational field.


Much different than your hand-tossed pipe-toy


You are confused
And this is observable in your descriptions


Taking the linear transform of angular momentum
You must include the vector
Non-parallel vectors subtract from one another
Leaving only difference, at the new vector.


I am focusing on the entire 5 seconds of fussy video
In your original post.


The cylinder is still rotating as it is released. (2s)
There is an angular momentum and associated
Angular velocity, as visible by the markings on
The pvc.
There is also a linear momentum of the system
As visible by the trajectory of the entire apparatus
Two Separate values, two different operations
Let's ignore the linear momentum for now
Even though it is far greater than any other momentum
In this system.
Let us focus on the rotational momentum
As the strings unwind, tension is placed on the strings
As a result of the (vector variant) angular momentum of each ball
At that moment, (2.8-2.9s on vid) the strings are at their maximum
Length. And as such are following their largest radius, and coincidentally
Traveling at their lowest velocity. Angular momentum at this point is
Subtracting from both the cylinder and the balls. Both balls combined
Are providing the torque on the strings which slows the cylinder and
Causes it to reverse directions.
The momentum of the balls (each) are subtracted by half of the total
Cylinder momentum that the cylinder had at (2s)
It was depleted across almost 1sec of time.
(This is why the balls are released!!!)
Immediately after this, the strings begin to shorten and the angular
velocity of the balls begins to increase.
This is accelerated by the cylinders (now opposite) rotation.
This continues for almost 3 seconds.
Until the strings are again completely wrapped.
Why 1 sec to unwrap, and more than double that to wind back up?
And the impact occurs at (5.9s)
The second reversal of the cylinder has already occurred at this point
Almost half a second before impact.
This is an effect of the linear velocity we are intentionally ignoring.
If gravity were not able to take control, and there was no linear momentum
To deal with, the cylinder and balls would spin back and forth
The cylinder changing directions twice every oscillation of the balls.
Like an odd flying pendulum. Until all of the energy has dissipated.
Which in your inefficient system, would probably occur before the 4th
full oscillation.

[sm0ky2]

They make these things for demonstrating physics labs
It's on a stick with a plastic knob you can spin with a pull string
The pull string is set just shy of one full rotation for the input.
This is meant for demonstrating momentum, not energy.
More importantly, it demonstrates how the momentum is
transferred between the two varying radii.
Via the attached points of the strings
The math is actually just like a pendulum
Or more accurately, like that of a kid on a swing that has
Enough balls to wrap the top post a few times.
Different kind of balls than the ones in your video.
But the momentum transfers just the same.
If the playground isn't bolted down a small child can
Tip it over like that.
Even though it weighs a lot more than the kid and has
Feet spaced for support.
The momentum of the kid is transferred into torque twisting
On the axis. Your "cylinder" in this case, is the upper beam
Holding the kid up. The entire playground, beam and all
Flip right over.


How did the kid build up so much momentum so quickly?
By wrapping the post with his swinging action, he shortened
The chains he was swinging on. Which caused him to move
Much faster.

[Delburt Phend]

This type of experiment was done by a student in Ohio.

[Delburt Phend]

I use several vertically mounted wheels that throw a single tethered mass. Two meters per second works just fine; that is why I chose it.

The sphere only stay 2 m/sec for a very brief period of time; it is soon 3 m/sec; and 7 ; and 20; and whoosh up it goes. Even in blaze orange you often never see them again.

What you see in the video is about 1/12 actual speed and with a low mass ratio 4.5 to 1. Most throws are much faster. 

Angular momentum does not work in the lab because there is no gravitation acceleration of the spheres; which is required for angular momentum conservation to be true.

Further more angular momentum conservation will give lower velocities for the spheres than energy. And energy conservation does not work because there is not enough linear momentum to return the original motion to the cylinder: which clearly happens.

I would like to see a picture of the playground equipment; sound like if you set that up in the U.S. you would be arrested.

The trouble with the playground equipment and the plastic knob stick thing; is that you are adding energy to the system. I can't envision either the knob or the playground thing, much like you can not envision a Atwood's with a 25 kilogram string on one side. 

If 'much faster' (in the last sentence) means linear velocity; then that is not true, linear velocity can not change without the application of outside force.

[sm0ky2]

In the U.S., what I was talking about is a normal playground
A-frames on the ends, an upper support bar, and swings hanging
from it.
I grew up in the 80's , these things were not bolted down back then.
Now we bolt the playgrounds to the ground or concrete the posts to
prevent this from occurring. (And other events that cause tipping)


I learned this the hard way, at a young age. Way before I understood
the physics that make it happen.


as far as your misconception concerning linear velocity of an object
That posses multiple vectored angular momentii......


My inertial propulsion research team got a big laugh out of your statement.


I am not even going to respond to it myself. I think I will let you stew on
That proposal for a moment.


Energy is always put into the system. The hand in your video inputs this energy.
In a controlled experiment, driven by a stepper motor, or even the rudimentary
pull-string- this energy is quantized. Meaning it holds an experimental 'value'
From which the data can be calculated.
Without knowing this value, you cannot perform energy conservation analysis.


If you did such analysis, you would probably go back and delete your posts.