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Article #1575Re: questions about light
From: PHYS2SHS
Date: Wed, 27 Apr 1994 19:57
Date: Wed, 27 Apr 1994 19:57
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>Just a comment about your answer to 2. below > > >> >2. If light is a particle, when it leaves a flashlight why doesn't it >> >have enough momentum to push the flashlight backward? >> >> No mass, no momentum, no recoil. >> >Though light doesn't have mass it still has momentum. This is the >principal behind the light sail for spacecraft. The momentum is given by > >p=h x frequency /c where h = Planck's constant and c is the speed of light. > >If the flashlight were not affected by forces such as gravity and friction >at its location it would indeed move backwards under the influence of the >weak force exerted by the photons. > >Ted van Nostrand >Holy Heart High School >St. John's, NF, Canada Thank's for the correction... Sorry about the misinformation (I was not think about light pressure .... GRSnow
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 16cfd8,55863ecabe0590e3 X-Google-Attributes: gid16cfd8,public X-Google-ArrivalTime: 1994-04-28 03:32:32 PST Path: arc1-ca.pugleaf.net!gmd.de!nntp.gmd.de!newsserver.jvnc.net!news.cac.psu.edu!psuvm!auvm!URIACC.URI.EDU!PHYS2SHS Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU Newsgroups: bit.listserv.physhare Message-ID: <PHYSHARE%94042716414998@PSUVM.PSU.EDU> Date: Wed, 27 Apr 1994 15:57:43 EDT Sender: Sharing resources for high school physics <PHYSHARE@PSUVM.BITNET> From: PHYS2SHS@URIACC.URI.EDU Subject: Re: questions about light Lines: 22