On Fri, 28 May 2004 12:49:04 +0100, Dave J <[email hidden]> wrote
(more or less):
Quoted message said:In MsgID<[email hidden]> within uk.rec.driving, 'Ambrose
Nankivell said:In news:[email hidden],
Dave J <[email hidden]> typed:
Quoted message said:The [censored] who is driving at less than the speed limit for no reason
(or because of their incompetence) is causing me (and themselves) to
burn *even more* of this horrid fossil fuel stuff, and to take *even
longer* to get to our destinations.
Urm, if you're going slower (within reason), then you're burning less of the
fossil fuel stuff.
No, you're burning it at a slower rate, but at a larger amount per
mile. I am thinking here of 40 limits, where a sensible person would
be doing 45 and an idiot may do 35. Definitely a drop in efficiency in
most cars.
Air resistance increases with the square of the speed.
Rolling resistance only increases with the speed.
Over about 15-20mph (for typical car body shapes), the increase in
power required to overcome the increase in air restance determines the
fuel efficiency / unit distance.
If you're really interested I can post the resistance/speed curves for
a typical car onto the web.
--
Cheers,
Euan
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