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Old August 2nd 05, 04:53 PM posted to uk.transport.london
asdf asdf is offline
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First recorded activity at LondonBanter: Feb 2005
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Default Warwick Gardens at night

On Tue, 02 Aug 2005 16:43:40 -0000, (Mark Brader) wrote:

Tony Bryer writes:
Being a old guy who passed his test in imperial days the formula for
stopping distance was m(1+m/20) feet: the first term is basically the
distance travelled whilst your brain is getting your foot to press
the brake, the second [that travelled in] the actual time needed to stop.


However, that is an oversimplification. The distance needed to stop
under maximum braking force (or any particular force) varies as the
*square* of the speed.


Which is presumably why the quoted formula has an 'm squared' in it
(once you expand the brackets).