Tony Smith <ajsmith@rivernet.com.au> wrote:
> > Most instructive for saving money were 3 demos
> > 
> > Jeremy Clarkson's London-Edinburgh-London trip in a V8 on one 
> > tank of diesel and similar tests on the track by both 
> > Mythbusters and a NZ motoring program. You can save 
> > substantially by driving conservatively, including reducing 
> > drag (windows and tailgate up) and weight (didn't Top Gear 
> > calculate it costs UKP6 a year to haul a moustache around ?)
> 
> In the second round of tailgate testing, there was a rather neat
> demonstration of E=MV^2, otherwise known as 'going twice as fast
> takes four times the effort'.
> 
> They ran the test at ~50 MPH (55?), and used 5 gallons or so.
> The next run was at 25 MPH, and only used 1.25 gallons.  (#s
> might off a bit...)
> 
> They never commented on it, but it was interesting to see a 'real
> life' example.

That has nothing to do with e = 0.5*m*v^2 (instantaneous energy),
and everything to do with the fact that most forms of resistance
(air resistance, rolling resistance, etc.) are proportional to v^2.
This means that the total energy (work) required to travel a given
distance tends to be proportional to v^2, and the power required
(work per unit time) is proportional to v^3.

-- Dave Tweed
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