On Fri, Feb 12, 2010 at 10:48:15PM +0800, Sandy Harris wrote: > On 2/12/10, Walter Hamler <[email protected]> wrote: > > Is 12 stories far enough to reach terminal velocity? > > My back-of-the envelope math says no: > > 12 stories, say 12 feet/storey as a round number. 144 feet. > > s = 16 t**2, so t**2 = 9, t = 3, a 3 second fall > > v = 32 t so it is doing 96 feet/second when it hits, about > 65 miles an hour.
I remember a bit more of the high-school maths class - there's no need to involve t in the calculations. From v^2 = 2fs we get v^2 = 2x32x144, or v = 96. Good - we seem to agree! -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
