More on fat people going downhill

I remembered a thread from the tandem mailing list a couple of years back
which caused a lot of confusion, so I shall see what people here (and on
cyclingforums) make of it:

My mate Arthur Pedaller has a really great bike. It has absolutely no
rolling resistance whatsoever - the sole retarding force is air resistance.
On a windless day he can happily pedal at 25mph, and he covers the 25 miles
to work on the marvellous straight road the council installed for him at
that speed.
But today's a bit windy - 10mph headwind to be precise. He decides to ride
at 15mph in order to make sure his hair doesn't look abnormal when he
arrives, and off he goes. Obviously he takes 1 hour 40 minutes to cover the
distance, but the question is, has he put in more or less work than on a
windless day?

cheers,
clive

Clive George wrote:
I remembered a thread from the tandem mailing list a couple of years
back which caused a lot of confusion, so I shall see what people here
(and on cyclingforums) make of it:

My mate Arthur Pedaller has a really great bike. It has absolutely no
rolling resistance whatsoever - the sole retarding force is air
resistance. On a windless day he can happily pedal at 25mph, and he
covers the 25 miles to work on the marvellous straight road the
council installed for him at that speed.
But today's a bit windy - 10mph headwind to be precise. He decides to
ride at 15mph in order to make sure his hair doesn't look abnormal
when he arrives, and off he goes. Obviously he takes 1 hour 40
minutes to cover the distance, but the question is, has he put in
more or less work than on a windless day?

Gordon Bennett, I dunno, but I bet the answer can be worked out via
http://www.analyticcycling.com

~PB

On 1/10/04 2:45 pm, in article
, "Clive George"
wrote:

I remembered a thread from the tandem mailing list a couple of years back
which caused a lot of confusion, so I shall see what people here (and on
cyclingforums) make of it:

My mate Arthur Pedaller has a really great bike. It has absolutely no
rolling resistance whatsoever - the sole retarding force is air resistance.
On a windless day he can happily pedal at 25mph, and he covers the 25 miles
to work on the marvellous straight road the council installed for him at
that speed.
But today's a bit windy - 10mph headwind to be precise. He decides to ride
at 15mph in order to make sure his hair doesn't look abnormal when he
arrives, and off he goes. Obviously he takes 1 hour 40 minutes to cover the
distance, but the question is, has he put in more or less work than on a
windless day?

Work done is Force applied times distance moved, W=Fd.

And one would presume that the distance is over the ground.

So no on a first glance.

But this is not the whole story. He has only done work in moving the wind so
we have to consider teh distance travelled through the wind.

In the first instance this is 25x1hours worth of air movement or 25 air
miles.

In the second case this is (15+10)x1hr40 worth of air miles, or 41.6 air
miles.

Going home he rides at 35mph all the way.. which takes him 43 minutes. His
work done is (35-10)x43mins worth of air miles.

So on the still day his return journey is 50 air miles. On the windy day his
return journey is 60 air miles (or near enough).

...d

Clive George wrote:
I remembered a thread from the tandem mailing list a couple of years
back
which caused a lot of confusion, so I shall see what people here (and
on
cyclingforums) make of it:

My mate Arthur Pedaller has a really great bike. It has absolutely no
rolling resistance whatsoever - the sole retarding force is air
resistance.
On a windless day he can happily pedal at 25mph, and he covers the 25
miles
to work on the marvellous straight road the council installed for him
at
that speed.
But today's a bit windy - 10mph headwind to be precise. He decides to
ride
at 15mph in order to make sure his hair doesn't look abnormal when he
arrives, and off he goes. Obviously he takes 1 hour 40 minutes to
cover the
distance, but the question is, has he put in more or less work than
on a
windless day?

cheers,
clive

Clive, if you weren't a regular I'd suspect someone was trying to get
some help with their homework. Have you started a GCSE physics course ?

"David Martin" wrote in message
...

But this is not the whole story. He has only done work in moving the wind
so
we have to consider teh distance travelled through the wind.

Are you sure? :-)

cheers,
clive

On 1/10/04 3:22 pm, in article
, "Clive George"
wrote:

"David Martin" wrote in message
...

But this is not the whole story. He has only done work in moving the wind
so
we have to consider teh distance travelled through the wind.

Are you sure? :-)

Yes. It is the same as the problem where the bloke in the boat rows upstream
and then downstream. It is Force x Distance moved. The Force is through the
air and the plane of reference for distance is to the moving air, not the
ground.


...d

David Martin wrote:

But this is not the whole story. He has only done work in moving the
wind so we have to consider teh distance travelled through the wind.

You and Ian SMith are one and teh same AICMFP ;-)

--

Dave Larrington - http://www.legslarry.beerdrinkers.co.uk/
================================================== =========
Editor - British Human Power Club Newsletter
http://www.bhpc.org.uk/
================================================== =========

"David Martin" wrote in message
...
On 1/10/04 3:22 pm, in article
, "Clive George"
wrote:

"David Martin" wrote in message
...

But this is not the whole story. He has only done work in moving the
wind
so
we have to consider teh distance travelled through the wind.

Are you sure? :-)

Yes. It is the same as the problem where the bloke in the boat rows
upstream
and then downstream. It is Force x Distance moved. The Force is through
the
air and the plane of reference for distance is to the moving air, not the
ground.

Are you really really sure? :-)

cheers,
clive

On 1/10/04 3:41 pm, in article
, "Clive George"
wrote:

"David Martin" wrote in message
...
On 1/10/04 3:22 pm, in article
, "Clive George"
wrote:

"David Martin" wrote in message
...

But this is not the whole story. He has only done work in moving the
wind
so
we have to consider teh distance travelled through the wind.

Are you sure? :-)

Yes. It is the same as the problem where the bloke in the boat rows
upstream
and then downstream. It is Force x Distance moved. The Force is through
the
air and the plane of reference for distance is to the moving air, not the
ground.

Are you really really sure? :-)

Are you bored?

...d

"MSeries" wrote in message
oups.com...

Clive, if you weren't a regular I'd suspect someone was trying to get
some help with their homework. Have you started a GCSE physics course ?

Hey - I've got an O level in physics - none of that GCSE nonsense!

cheers,
clive