Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

See http://peswiki.com/index.php/Directory:Milkovic_Two-Stage_Mechanical_Oscillator

The Two-Stage Mechanical Oscillator Pendulum-Lever System is very simple, yet very puzzling because it appears that more energy is going out (since it is able to pump water) than is put in (only lift one lift of the pendulum and an occasional push).

Where is the apparent excess energy coming from? The reason I am asking this question is because all of the explanations I have seen claim that somehow Newton's Laws are violated, which I cannot believe.

share|improve this question
add comment

2 Answers

up vote 1 down vote accepted

Well that was an interesting waste of time. I'm trying to imagine poor Albert Einstein working in the patent office spending his time debunking stuff like:

  • hammering something against friction and saying "gee, it moved - that proves overunity"
  • rolling a cart against friction and saying "gosh it moved farther"
  • making a gadget with a pendulum, standing there pushing it, something heavy at the other end moves a little bit, and saying "gosh - free energy"

I do have to admit, those toys were well made.

But a perpetuum mobile has to run "forever" with no input, indeed with net output.
EDIT: The apparent energy output is just that - apparent. Not one of the gadgets could run by itself.

share|improve this answer
    
This is not an answer. This is just an opinion. –  Craig Feinstein Feb 28 '12 at 3:14
    
@Craig: I watched the videos. Check the edit. –  Mike Dunlavey Feb 28 '12 at 13:29
    
How do you know that the apparent energy output is only apparent? I agree that friction eventually overcomes the pendulum, but what if the energy from the output of the gadget were used to drive the pendulum? –  Craig Feinstein Feb 28 '12 at 16:26
    
@CraigFeinstein It wouldn't be enough. That video shows a tiny amount of water going up. Plus, the pendulum is actually quite heavy, which makes the energy input large. –  Manishearth Feb 28 '12 at 17:17
1  
@Craig: The burden of proof is on the person claiming it's a perpetual motion machine. He didn't even attempt to measure the energy per unit time going in or coming out. At the very least it should run by itself for a long time. –  Mike Dunlavey Feb 28 '12 at 18:43
show 5 more comments

The explanation is quite simple.

1) The big lever is used to "store energy"

2) When the pendulum is in the lowest point, the lever holding pendulum pivot will drop by height H, thus accepting mechanical energy equal to H x (F + G), where G is the weight of the pendulum (gravitational force = m x g) and F is the centrifugal force. If this drop occurs in the lowest point, it does not affect the movement of the pendulum, because the respective acceleration is perpendicular to the movement of the pendulum (it cannot hang on a wire, the connection between pendulum and its pivot must be stiff). The drop decreases the POTENTIAL energy of the whole pendulum system (pivot and pendulum) and stores it as increase of POTENTIAL energy of the opposite side of the lever.

3) When the pendulum is rising, the big lever comes out of balance, because the vertical force on the pendulum pivot decreases. The pivot is raised and pendulum kets a "kick", but at this time parallel or almost parallel to the upward movement. This kick increases KINETIC energy of the pendulum. This energy is taken from decrease in POTENTIAL energy of the lever. Previously stored POTENTIAL energy is transformed to KINETIC energy.

4) Where does the energy increase come from? Well, the POTENTIAL energy in this system obviously comes from gravitational force. In full accord with Newton's third law, when the whole system "pumps" potential energy, there is an opposite movement of the other body that causes the gravitational force. Which is the Earth... Thus, every "drop" is accompanied by a "raise" of the Earth, but that is of course immeasurable quantity due to the huge ratio between mass of the Earth and mass of the pendulum-lever system. It is similar when you launch a rocket or jump on your feet. Your feet push the Earth away a little bit, but this little bit is negligible compared to the height of the jump.

So, the guy who said that Two-Stage Mechanical Oscillator is a claimed "perpetuum mobile" should go back to Junior High or whatever is their country's basic education institution and let some teacher explain them again the Newton's three laws of motion. In energy analysis you cannot just deliberately neglect one element of the whole system. If you do that, your result will be nonsense.

share|improve this answer
add comment

protected by Qmechanic Jan 27 '13 at 19:33

Thank you for your interest in this question. Because it has attracted low-quality answers, posting an answer now requires 10 reputation on this site.

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged or ask your own question.