There is of course greater friction when moving an object through fluids of greater density, However a boat, sitting in a fluid at rest, will move, if pushed by even the slightest force. This would also apply if ball bearings were perfectly round. because their surfaces would not touch the race,due to the principle that it is impossible for a perfect sphere to touch a perfectly smooth surface as the point of contact is infinite. Having said that. one early morning I happened upon a moored 100 ton barge loaded with coal floating in the canal which had a looking glass surface, the mooring ropes were limp, the barge was totally at rest as was the air and the water surrounding it. I applied force with my little finger not more than 1lb. to see if it would move, nothing happened at first but then the barge began to move in the direction it was being pushed, I just cannot see a vehicle other than a vessel moving with such a small force being applied.
GF -----Original Message----- From: Pete & Sheri <[email protected]> To: 'Discussion of biomass pyrolysis and gasification' <[email protected]> Sent: Thu, May 26, 2011 12:48 pm Subject: Re: [Gasification] OT, now, Boat pulls easier than Cart? I'm sorry, but I disagree with your comments that the cart would have more riction than the boat, loaded or ot. The density of water vs air has a lot to do with it. But the two main riction sources to compare would be water friction vs bearing and heel-to-surface friction of the vehicle. I'd agree with you if the cart ad no wheels and had to be dragged down the road as the boat has to be ragged in the water, but this is not the case. In the history of west in the USA, people used sails on "covered wagons" for otive power. They worked okay as long as there were relatively smooth urfaces to run them on. Google this: ttp://en.wikipedia.org/wiki/Land_sailing Pete Stanaitis ---------------- -----Original Message----- rom: [email protected] mailto:[email protected]] On Behalf Of Anand arve ent: Thursday, May 26, 2011 10:57 AM o: Discussion of biomass pyrolysis and gasification ubject: Re: [Gasification] Underwater gasification? Dear Henri, ou have misunderstood me. I said that hauling a boat floating in ater was easier than pulling a cart on land. I was comparing the riction of the boat with water with the friction of a loaded cart on and. The density of air and water have nothing to do with it. I entioned air only as a motive force. Wind can move a boat easily hrough water but the wind of the same velocity would be unable to ove a cart on a road. ours .D.Karve _______________________________________________ asification mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page ttp://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org for more Gasifiers, News and Information see our web site: ttp://gasifiers.bioenergylists.org/
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