[geeks] lawn mowing efficiency

[David Cantrell]

On Sun, Apr 21, 2002 at 03:42:35PM -0500, Bill Bradford wrote:

> I was "taught" to mow lawns, with a eject-on-the-right-side mower, was
> to do it in a spiral, or squared-spiral, counterclockwise so that you
> never had to go over the grass you'd just mowed and ejected on the right-
> hand side.  Like this (monospaced fonts ahead!)
> 
> |
> |/-----\
> ||/---\|
> ||\---||
> |\----/|
> \------/
> 
> Till you end up in the middle (or darn near close to it) of a freshly mowed
> lawn.  
>
> I was wondering.. this is probably a math problem.. is there a more efficient
> way (less walking distance) to mow the same area?  Which is longer, the "spiral"
> way or the "rows way (see below)?
> 
> |
> |/\/\/\|
> ||||||||
> ||||||||
> ||||||||
> \/\/\/\/

Well, count the characters in each of those.  Same distance covered in each
one.  However, you should really be concerned not with the least walking
distance but with expending the least amount of energy.  Doing it in rows
requires several 180 degree turns, whereas the spiral requires a larger
number of 90 degree turns.  I imagine that a 90 degree turn requires less
energy than a 180 degree turn, but that that will at some point be cancelled
out by the increased number of turns required.  I suggest that you experiment
by mowing several lawns of different sizes.  Not only will you be advancing
the boundaries of science, but your neighbours will love you for it too.

-- 
David Cantrell    |    Reprobate    |    http://www.cantrell.org.uk/david

  Any technology distinguishable from magic is insufficiently advanced