energy producing experiments

[pequaide]

coupler with 3 in. and 4 in. pipes

[broli]

Can I make this experiment in wm2d?

[pequaide]

What is wrong with PVC? Science catalogs sell the spheres.

[pequaide]

Computer programs are programmed by prejudiced programmers. When you are trying to overcome faulty concepts in science you need experiments. Experiments are not influenced by the experimenter’s opinion. Computer programs spit out the information you feed in. In this situation they are of no more value than computer animations, if you want the computer program to conserve angular momentum it will do so. If you what the computer program to conserve linear Newtonian momentum it will do that. It can not conserve both of course. So the computer program is of no value in determining which of these laws is being correctly applied. You need to do an experiment that separates the chaff from the wheat.

NASA actually graphed how far wrong they expected to be with the yo-yo de-spin device. They did not need to be wrong they could have hit it dead on the nose if they had used the correct law.

[Jonathan]

I think it ended up going 3rpm backwards because the strings were not released radially, they were wound around the circumference: when they fly outward, they swing in the opposite sense than the craft is spinning, which causes it to stop and reverse. IIRC, releasing the strings radially would have prevented the craft from reaching zero spin, because the strings would have to be infinitely long (proving this requires that you acknowledge the laws I use though).
If you are interested, I can show you how conservation of angular momentum is actually a consequence of conservation of linear momentum; perhaps you will correct me. (To be sure I don't make mistakes, I will wait for a friend to return this week the textbook that I loaned to him, which I recommend to everyone: Analytical Mechanics, by Fowles and Cassidy; Lord only knows how I remember their names).
(EDITTED from original)

[broli]

Jonathan how is citing a book going to prove an experiment? Sure it can predict it but that's not the point pequaide's setup. It's silly to use formulas and laws while the experiment is meant to show these laws don't always hold, the conservation of energy one to be exact. I have nothing majorly against newton's law since they don't talk about energy conservation. Newton himself thought about a gravity shield for endless motion.

[Jonathan]

The reasons are:
1) these kind of experiments are difficult to do, since things happen fast;
2) experiments aren't perfect because their results must be interpreted;
3) I think his opinions are not logically consistent, and it is easier to check this with math than with experiment.

[pequaide]

Jonathan quote: these kind of experiments are difficult to do, since things happen fast;

pequaide; I use a digital video camera that slices a second into 30 equal parts, and strobe light photography (set at 1/100 of a second), and a photo gate timer (different modes). Most of these things can be found in a High School lab.

Jonathan quote: experiments aren't perfect because their results must be interpreted;

pequaide: And books are perfect? I would hope books are based upon experiments.

Jonathan quote: I think his opinions are not logically consistent, and it is easier to check this with math than with experiment.

pequaide: If a ballistic pendulum conserves linear Newtonian momentum then its reversal should conserve linear Newtonian momentum. I think that is eminently logical. The books are wrong; you have to experiment to find out who is correct. If I am correct we are looking at five trillion dollars. And the experiments cost $15.

[pequaide]

When the small gray mass swings out it quickly stops the spinning wheel off to the right.

[pequaide]

Sometimes I have access to my computer but I am not in the lab, so let me continue to argue against angular momentum conservation (in the lab).

An average size new construction home could be installed with a seven meter rim mass wheel. The cylinder or white disk could be .25 meters (dia.). So, according to the angular momentum conservationists, the thrown gray disk could then be given all the “angular momentum� of the seven meter rim. Wow, you could launch bullets.

The angular momentum formula states that a 100 kg rim with a circumference velocity of 1 m/sec and having a radius of 3.5 meters will have seven times as much angular momentum as a 100 kg rim with a circumference velocity of 1 m/sec and having a radius of .5 meters.

Angular momentum conservation would require this sequence of events. When all the motion of the seven meter rim has been given to the gray disk (corresponding to the above pictured experiment) in paragraph two and the disk has a mass 1/10th that of the seven meter rim, then the gray disk will have to have a velocity 140 times larger than the original velocity of the seven meter rim.

I am expecting little league baseball speeds not bullet speeds, but ha who am I to complain.

As far as collecting data from the above experiment, that is always the objective of a good experiment. But the data has already been collected. There is a substantial quantity of data collected from the cylinder and spheres. The experiment with the detached wheel and connecting ribbon only shows that the rotating mass need not be contained in the cylinder, and of course that the radius of the rotating mass has no effect upon the ultimate velocity of the final mass in motion. All data collected from the cylinder and spheres experiment shows that linear Newtonian momentum is conserved and that energy has been made in the laboratory. The external wheel and red ribbon experiment points to even more useful applications.

[pequaide]

In the picture of the white disk you will see a white nylon cord attached to the gray disk. The cord was fastened using a slip knot and secured to the gray puck with gray duck tape. As the system begins spinning the gray puck tries to leave the system on a line tangent to the white disk. The white nylon cord tries to prevent the gray disk from leaving the system and soon all the motion is in the gray disk.

The experiment is arranged so that the spinning motion of the 18 inch drive wheel is transferred to the white disk on the table. The red ribbon combines the momentum of the drive wheel to the momentum of the white disk. The white disk is horizontally mounted and has a mass of 485 grams. The velocity at the circumference times its mass (which is distributed throughout the disk) gives it a rotational momentum. This momentum of the white disk is about equivalent to 300 grams that were located on the circumference. The rotational momentum of the 3,400g drive wheel is roughly equivalent to a 2,200g rim times its circumference velocity. The center of mass of the 456g gray disk is on the circumference of the white disk so its rotational momentum is roughly equal to 456g times the circumference velocity.

Let’s use 1 m/sec for the ribbon velocity; this gives you 1 m/sec circumference velocity for the wheel and white disk and 1 m/sec velocity for the center of mass of the gray disk.

This gives you an initial linear Newtonian momentum of 2.956 newtons (2,200g + 300g + 456g * 1m/sec)

This gives you an initial kinetic energy of 1.478 joules (1/2 *(2.200kg + .300kg +.456kg) * 1m/sec * 1m/sec)

This gives you and initial angular momentum of .5701 (2.200 * .2286 m + .300kg * .0889m + .456kg * .0889m * 1 m/sec)

For conservation of linear Newtonian momentum the gray disk will be moving 6.48 m/sec when it has all the motion.

For conservation kinetic energy the gray disk will be moving 2.54 m/sec when it has all the motion.

For conservation of angular momentum the gray disk will be moving 7.03 m/sec when it has all the motion.

If you used a larger drive wheel angular momentum conservation would give you a final velocity that would be off the charts.

If Newtonian linear momentum is conserved at 6.48 m/sec the final kinetic energy is 9.57 joules.

[pequaide]

better view of larger drive wheel

[pequaide]

Correction: a newton is a unit of force not a unit of momentum, Sorry. I have to watch my terms.

[DrWhat]

Pequaide, I don't have anything to add but I am reading with interest.

[ruggerodk]

pequaide:

You mention a grey disk, a grey puck, a white disk and a drive wheel...

Sorry, but I'm confused!
Are the grey disk and grey puck one and the same?
Or do we count four (4) disks/wheel in total?

Also, I find it very difficult to see the white cord attachment (perhaps my old eyes)...Is it possible for you to point these attachments out by insertion of arrows, for clarity?

Even though I'm not skilled in mathematics I find this very interesting...Keep it up ;-)

all the best
ruggero ;-)[/b]