Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site cci-bdc.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!genrad!mit-eddie!cybvax0!cci-bdc!jlup From: jlup@cci-bdc.UUCP (jrl devlt) Newsgroups: net.physics Subject: Re: A new improved perpetual motion machine Message-ID: <176@cci-bdc.UUCP> Date: Wed, 10-Apr-85 20:09:12 EST Article-I.D.: cci-bdc.176 Posted: Wed Apr 10 20:09:12 1985 Date-Received: Thu, 18-Apr-85 04:31:23 EST References: <489@vax2.fluke.UUCP> Distribution: net Organization: Computer Consoles, Inc., Cambridge, MA Lines: 108 > Ok perpetual motion machine fans, see if you can explain this one. This was > presented to me several years ago by a friend, and even though we both "knew" > it couldn't work, no one was ever able to tell us why. > > Start with a vessel, like a cup, with a weight resting in the bottom and a > flexible diaphragm stretched across the top. The bottom and sides are rigid. > It might look something like this- > > H-----------H > H _ H > H / \ H > H | | H > \\ \_/ // > ========= > > Now if we invert the vessel and allow the diaphragm to stretch, the volume > increases, while the internal air pressure decreases. > > ========= > // \\ > H H > H H > H H > H\ _ /H > \ / \ / > \| |/ > \\_// > - > Since buoyancy is related to volume displaced, the inverted vessel should be > more buoyant than the upright vessel. By making use of that property, we > now construct our perpetual motion machine by linking many of these vessels > together in a chain and submerging them under water (in theory any fluid > should work). > > <- > > o > / \ > u O > | | > u O > | | > | u O ^ > v | | | > u O > | | > u O > | | > u O > \ o / > > -> > > There you have it, free energy! The inverted vessels on the right provide > greater buoyance than those on the left so the net result is an upward force > on the right greater than that on the left. > > Who can tell me what is wrong with this picture? > > Craig Johnson uw-beaver! \ > John Fluke Mfg. Co., Inc. decvax!microsof! \ > Everett, Washington ucbvax!lbl-csam! > fluke!vince > allegra! / > ssc-vax! / The reason this will not produce any new energy (as might be required in order to overcome frictional losses, etc.), is that the energy to be gained by taking advantage of the added buoyancy is the same energy used to increase the volume of the vessel. At the top, there is a transition from the hi volume state to the low volume state. The energy balance for a box drawn around the top "pulley" is, assuming vacuum inside and very slow speed (no kinetic effects - not a needed condition as kinetic effects cancel, but I don't want to bother showing this, someone else can): 1) the potential energy of the upward bound vessel: i) energy stored in the deformed diaphram. ii) gravitational potential of the vessel. iii) gravitational potential of the weight. iv) bouyant potential of the vessel. 2) the potential energy of the downward bound vessel: i) energy *not* stored in the *undeformed* diaphram. ii) gravitational potential of the vessel. iii) gravitational potential of the wieght. iv) bouyant potential of the vessel. Assuming that one upward bound vessel enters the top box at the same time as a downward bound vessel leaves, energy conservation shows that the difference between these two energy states is reflected in tensions in the string. The point is that the operations at the bottom, with respect to energy balance, are the exact converse of this situation. The work used in distending the diaphram is *exactly* equal to the weight of water displaced times the hieght of displacement, both at the top and the bottom, and is thus exactly exactly equal the work obtained from the change in buoyancy (the weight of water displaced times the distance of translation). This scheme works as well as any other "classical" system of perpetual motion: only without friction. -John