Newsgroups: comp.robotics
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From: mds@iastate.edu (Mark D. Smucker)
Subject: Re: Measuring the acceleration of an arrow.
Message-ID: <ByLn2B.EoH@news.iastate.edu>
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Organization: Iowa State University of Censorship and Repression
References: <1992Nov22.203815.9006@hemlock.cray.com> <20373@acorn.co.uk> <168B09AEC.CCEB001@UTXVM.CC.UTEXAS.EDU>
Date: Tue, 1 Dec 1992 21:15:45 GMT
Lines: 31

>>First we were going to tape a piece of 8mm movie film to the arrow and have
>>a LED blinking on and off to generate light and dark strips on the film as
>>the arrow/film flew past the LED. I tried this with a stick and gravity and
>>I came up with a good value for the acceleration due to gravity. But it was
>>messy and I wasn't too cool about shooting arrows in the dark and then trying
>>to find the film and develop it.

Why not just use ticker tape?  

In most physics class labs, you use a ticker tape to measure
acceleration and velocity etc.

Some tapes are pressure sensitive and put a mark on the tape at
regular intervals.

But, the system I like the most was one that used an electronic
sparking system to place the marks on a tape. 

So, all you would have to do would be to:

	1) tie the tape to the end of the arrow
	2) have tape on a spool ( or some sort of pile so that you
	wouldn't have to be concerned about the rotational inertia. )
	3) start the spark system
	4) shoot the arrow.

Of course, this is a tedious, non precise method, but cheap and fairly
easy.

Mark D. Smucker   -----    mds@iastate.edu

