On Fri, 2 Oct 2009 17:42:17 -0700 (PDT), Frogwatch
wrote:

On Oct 2, 8:02*pm, brian whatcott wrote:
Goofball_star_dot_etal wrote:

...

Hmmmm. a mostly reasonable review - but the idea that force times
distance *is not equal to work is somewhat radical, don't you think?

I said no work was done *on the (air)plane*. Since we only have the
airplane and the air, the work done by the thrust of the engine moving
the airplane through a distance all goes into the air as (kinetic)
energy or heat in its wake.

If I push a sled over snow with force F for distance D
it's usually accounted that the work I did ON the sled is F X D

...but I won't beat the topic down....
:-)

Brian W

In regard to sudden gusts, why not use a breakaway strap like some
rock climbers use whose stitches break at some load allowing the sail
to be let out all the way.
How many boats get knocked down anyway? I mean cruising boats, racers
intend to be on the edge. My own boat, a 28' S2, if a sudden gust
came up, I'd never be able to hold the tiller and she'd round up into
the wind before getting knocked down.

Guess again!