Another claim to a working device...

[Grimer]

I interpret that question as what make me think the two will come together if you incorporate the suggestions I made in my PM.

Fair question.

Well the "grainyness" of the interaction between a mass of 1 and a mass of 15 is quite coarse so I would expect the quantum (using the word in the general sense, not the specialized sense) to be also coarse.

But it isn't. It's very small, and that suggests another cause to me, namely the one I gave you in my PM.

Does that answer your question?

Edit: If one stepped up the simple pendulum to 2 and stepped down the compound pendulum to 8+6 then there would be a step change in the positions reached. This step change would be much larger than the small difference we are talking about.

That step change is the grainyness.

[Grimer]

I've now got to take my grandchildren to school. I'll be back later.

[Tarsier79]

Here is the modified sim.

There is some jiggery pokery to move the impact to COM of the pendulum, and exactly 6:00. The result is still the same.

If one stepped up the simple pendulum to 2 and stepped down the compound pendulum to 8+6 then there would be a step change in the positions reached. This step change would be much larger than the small difference we are talking about.

Nice try, but no cigar.

1. The simulation acts according to understood laws of motion.

2. The pendulums speed is determined by its height loss.

3. More complex formulas I am not educated on are used for the impact: the result is the energy the pendulum gives up is subtracted from its rebound, giving it a new maximum PE. The same amount of energy subtracted from the simple pendulum is added to the compound pendulum.

4. The compound pendulum achieves the exact gain in PE that the simple pendulum lost. Due to this constraint, (however it is calculated) WM2D will not show you a gain using this mechanism, unless there is a calculation error.

So: we will get an equivalent result if we impact at 4:00, 5:00 or 8:00 (or anywhere between).

We will also get the same result regardless of the placement of the impact point, provided it is a perfect impact at 0 degrees to direction of travel at the moment of impact.

[Grimer]

I can't open that file. Could you put it on your YouTube site please.

[Grimer]

Do you agree that if the single pendulum were to reach the perfect balance point (it is only a very short way from it) then there would be a lot of angular momentum in the system which would rotate the "wheel" around indefinitely given no friction.

Surely, you second video shows this. The only reason it stops is because the beam is not fully balanced and keels.

Edit: Correction

The reason it stops is because it lifting the difference between 8 weights and 7 weights and it uses up the impetus given it by the simple pendulum fall.

[Grimer]

Having looked at it again I can see that you won't agree. I'll have to think about this and wonder if the sim is at fault in the way it treats impact - or if I am looking at things the wrong way. I'm not infallible. ;-)

I must admit I was surprised the beam didn't rotate more in view of the fact that it was virtually balanced.

[Grimer]

There's something not right about the sim. I'll have to download it, get some screen shots and explain.

However, it seems clear the sim is not going to produce the incontrovertible evidence I had hoped so we had better put it on the back burner for the time being.

I have other stuff which shows that the frame of reference for momentum moves when moving body impacts a stationary body but I'll hang onto that for the time being.

[Grimer]

Thinking about it there is something fishy with the way the beam slows down so much as it goes to 12 o'clock. The beam is so nearly in balance - remember that the 7 weight is exactly in balance and the 1 weight is only very slightly out of balance. I suspect the balance aspect has been ignored in some way.
Possibly the contribution of the single pendulum weight to the balance has been ignored. That would explain it.

Exciting - ain't it. :-)

[Grimer]

If the addition of the single weight to the 7 weights is ignored then one has 8 weights and the left hand end and 7 weights at the right hand end.

Difference one weight.

The 8 end has been given enough energy to lift one weight to 12 o'clock which it does. It lifts the difference between the 8 weight and the seven weight and the video looks exactly as one would expect if that was going on. Also, why should a virtually perfectly balance beam stop at 12. It would stop eventually because it's not perfectly balanced but it would rotate may time before it did.

The sim has not attached the 1 weight to the seven weight to give a balanced beam.

(I've managed to download the video from YouTube. Very nice)

[Ed]

Frank, I don't think the video would look as nice if the sim had accounted for all the real-world losses.

[Grimer]

We are not talking about the real world, Ed. We are talking about applied maths and boundary conditions.

[Grimer]

Big eyes. ;-)

You can keep the cigar but I would be interested in your comments.

[johannesbender]

most likely it does not rotate long because
the impact is just like a Newton cradle but with
different masses , perhaps you need to increase
the swinging weight..

edit: are those thin arms , springy ?

[daxwc]

Grimer:

I must admit I was surprised the beam didn't rotate more in view of the fact that it was virtually balanced.

Why does it take a heavy flywheel longer to get up to speed than a light one? Why does the heavy flywheel have more stored energy?

[Grimer]

The most amusing detection of error I ever made was an occasion in the Steorn Forum.

Shawn McCarthy was claiming the they had a "big engine". He was being pressed for details of it and eventually he said it was 550 bhp. I immediately called him a liar. Didn't the other forum members give me some stick - didn't they just.

The reason I called him a liar is that I realised he had just plucked the figure out of thin air. Unfortunately for him 550 is a well know number in Imperial Units.

Definition. — The Unit of Power, called the Horse-power, is
the rate of doing work corresponding to 550 ft.-lbs. per second,

Three months later he finally admitted that he had indeed lied. There was no big motor, no little motor, no motor at all.

Steorn is the kind of company that gets the search for new energy a bad name.

Attached is the Economist advert heralding that wild goose chase.

And before an evil minded some one accuses me of insinuating that Tarsier79 has sabotaged the sim - I am certainly not.