Article View: sci.electronics
Article #21596Re: Re^2: HV Cap Fun!
From: Anthony E. Siegman
Date: Fri, 02 Jun 1989 22:41
Date: Fri, 02 Jun 1989 22:41
10 lines
1266 bytes
1266 bytes
There's a mechanical analog to the switched-capacitor "where did half the energy go" problem. A slow conveyor belt rolls past a loading chute which dumps dirt or coal or something on the belt at a fixed rate dm/dt (m=mass of dirt dumped). The dirt is instantaneously accelerated to the belt's steady velocity v as it hits the belt's surface. Force required to keep pulling the belt (no friction) = f = dp/dt where dp = dm v = momentum added to the mass dm. Work done in time dt = f dx = dm v^^2 (using dx = v dt). But kinetic energy added to (or carried by) the dirt is only (1/2) dm v^^2. Where's the other half?
Technical Details
Message-ID:
<148@sierra.stanford.edu>Path:
arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!ucbvax!agate!shelby!labrea!siegman@sierra.Stanford.EDUReferences:
<4924@m2c.M2C.ORG> <3806@mit-amt> <20772@quacky.mips.COM> <166@mother.dde.uucp> <147@sierra.stanford.edu> <2329@quanta.eng.ohio-state.edu>Show Full Headers
Complete Article Headers
Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!ucbvax!agate!shelby!labrea!siegman@sierra.Stanford.EDU From: siegman@sierra.Stanford.EDU (Anthony E. Siegman) Newsgroups: sci.electronics,sci.physics Subject: Re: Re^2: HV Cap Fun! Message-ID: <148@sierra.stanford.edu> Date: 2 Jun 89 22:41:47 GMT References: <4924@m2c.M2C.ORG> <3806@mit-amt> <20772@quacky.mips.COM> <166@mother.dde.uucp> <147@sierra.stanford.edu> <2329@quanta.eng.ohio-state.edu> Sender: siegman@sierra.STANFORD.EDU (Anthony E. Siegman) Reply-To: siegman@sierra.UUCP (Anthony E. Siegman) Organization: Stanford University Lines: 10