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For a relatively higher bridge would you expect a larger or a smaller
error.  I am thinking that the time to push the button is constituent
and the total time is greater resulting in a smaller error.  If you
let go a few of those steel balls into the ocean from a hight of say
30 meter what might one expect?
Thomas A. Sult, MD
3rd Opinion
1415 First First St. South #5
Willmar, MN 56201
320 235 2101 Office
www.3rdOpinion.us
tsult@mac.com






On Jun 22, 2011, at 5:58 PM, Bill Morris wrote:

> I thought I would discover how well the rock-throwing method might
> work for me in practice. To avoid discussion about the behaviour of
> feathers and the shape of rocks, I used petanque balls. These are
> polished steel balls of 72 mm diameter and weighing 500 grammes,
> used in the game of petanque (q.v.).
>
> I threw them horizontally from the bridge of our ship
> "Baradozic" ("Little Paradise" in the Breton language - my wife is
> from Brittany)and used a stop watch reading to 0.01 second to time
> their fall onto level ground a measured 5.8 metres below.
>
> The mean time of 25 throws was 1.29 seconds, with a standard
> deviation of 0.087 seconds, so that we could expect 95 percent of
> the times to fall in the range 0.95 to 1.63, as indeed they
> comfortably did (1.04 to 1.47).
>
> Taking the local acceleration due to gravity to be 9.805 metres/s/s
> gives a height of 8.16, an error of nearly 30 percent. This would
> give a dip error of 0.8 arcmin.
>
> The error is in the right direction. If one assumes a timing error
> of 0.1 seconds (and you don't have to be old and decrepit to have
> such an error when operating a stop watch), we get a much closer 6.9
> metres.
>
> The linked photograph shows the bridge of the Baradozic ;-)>
>
> Bill Morris
> Pukenui
> New Zealand
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