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#2
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Gene Nygaard wrote:
"What is the relevant factor here -- that it is pressing down with a force due to gravity of 9000 pounds due to gravity of 9000 pounds force? Or that it has a mass of 9000 pounds? The tonnage of a ship is the weight of the water it displaces. The force pressing down (normal force) in mechanical problems is significant when friction is involved. Force equals mass time acceleration. So, the mass opposes and increases the force required to get an object moving, or slowed, for that matter. That includes a ship. It has inertia and requires force to change its velocity. Drag is imposed on the submerged portion of the hull, especially when coated with barnacles. I shipped out of Long Beach in WW-2 on the LSM 472. I returned to San Francisco on the LSM 94. I was transferred to the LST 604 to take it up river to Stockton to be decomissioned and scrapped. While at the ship yard there I witnessed a curious sight. A large merchant vessel was moved from one berth to another using a small boat with an outboard motor as the tow boat. River current in the basin was almost nil, yet it took several hours to move that large ship with the power of only an outboard motor. It worked! There must have been nothing more powerful available and there must have been no rush to get the berth swap made. Point is that it is likely that neither mass nor weight is as important as current in many situations. How soon you can get up to speed depends a lot on mass as Newton predicts. That motorboat would have done its thing much more quickly with a waterskier in tow than it did with a big merchant ship in tow. Best regards, Richard Harrison, KB5WZI |
#3
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On Wed, 1 Oct 2003 00:36:15 -0500 (CDT),
(Richard Harrison) wrote: Gene Nygaard wrote: "What is the relevant factor here -- that it is pressing down with a force due to gravity of 9000 pounds due to gravity of 9000 pounds force? Or that it has a mass of 9000 pounds? The tonnage of a ship is the weight of the water it displaces. The force pressing down (normal force) in mechanical problems is significant when friction is involved. Force equals mass time acceleration. So, the mass opposes and increases the force required to get an object moving, or slowed, for that matter. That includes a ship. It has inertia and requires force to change its velocity. Drag is imposed on the submerged portion of the hull, especially when coated with barnacles. I shipped out of Long Beach in WW-2 on the LSM 472. I returned to San Francisco on the LSM 94. I was transferred to the LST 604 to take it up river to Stockton to be decomissioned and scrapped. While at the ship yard there I witnessed a curious sight. A large merchant vessel was moved from one berth to another using a small boat with an outboard motor as the tow boat. River current in the basin was almost nil, yet it took several hours to move that large ship with the power of only an outboard motor. It worked! There must have been nothing more powerful available and there must have been no rush to get the berth swap made. Point is that it is likely that neither mass nor weight is as important as current in many situations. How soon you can get up to speed depends a lot on mass as Newton predicts. That motorboat would have done its thing much more quickly with a waterskier in tow than it did with a big merchant ship in tow. So what is the SI equivalent of those 27,561 tons deadweight for that U.S. Navy ship? Gene Nygaard http://ourworld.compuserve.com/homepages/Gene_Nygaard/ |
#4
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Gene wrote,
So what is the SI equivalent of those 27,561 tons deadweight for that U.S. Navy ship? Gene Nygaard http://ourworld.compuserve.com/homepages/Gene_Nygaard/ I asked first. Why are you spamming the newsgroup with off-topic posts? 73, Tom Donaly, KA6RUH |
#5
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On 01 Oct 2003 14:59:45 GMT, (Tdonaly) wrote:
Gene wrote, So what is the SI equivalent of those 27,561 tons deadweight for that U.S. Navy ship? Gene Nygaard http://ourworld.compuserve.com/homepages/Gene_Nygaard/ I asked first. Why are you spamming the newsgroup with off-topic posts? You seem to be operating under several delusions. I'm not spamming. I didn't start this discussion. The discussion I entered was not off topic here. You yourself, while you have contributed to the on-topic discussion, have also been responsible for more thread drift in this thread than anyone else. Democritus? Good grief! There wasn't anything on-topic in the message in which you brought him up. What connection do you find between him and the definition of ohms, and the inaccurate analogy using faulty defintions of pounds that lead to my entry into the discussion? Gene Nygaard http://ourworld.compuserve.com/homepages/Gene_Nygaard/ |
#6
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Gene wrote,
You seem to be operating under several delusions. I'm not spamming. I didn't start this discussion. The discussion I entered was not off topic here. You yourself, while you have contributed to the on-topic discussion, have also been responsible for more thread drift in this thread than anyone else. Democritus? Good grief! There wasn't anything on-topic in the message in which you brought him up. What connection do you find between him and the definition of ohms, and the inaccurate analogy using faulty defintions of pounds that lead to my entry into the discussion? Gene Nygaard http://ourworld.compuserve.com/homepages/Gene_Nygaard/ Nope, you're spamming. The subject you keep harping on has very little to do with antennas. Evidently, it's so overwhelmingly important to you that you're willing to hand out gratuitous insults and a never-ending series of posts to those you perceive as not agreeing with your narrow understanding of the subject. I'm reminded of Samuel Johnson's friend who only had one idea in his head, and that a wrong one. While you're not alone here in being possessed of an overwhelming obsession, at least the obsessions of the others bear some relation to antenna and transmission line theory. Personally, I don't much care what you do, but I'm curious as to why you do it. How can such a small idea trigger such a large obsession? 73, Tom Donaly, KA6RUH |
#7
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On Wed, 01 Oct 2003 08:54:56 GMT, Gene Nygaard
wrote: On Wed, 1 Oct 2003 00:36:15 -0500 (CDT), (Richard Harrison) wrote: Gene Nygaard wrote: "What is the relevant factor here -- that it is pressing down with a force due to gravity of 9000 pounds due to gravity of 9000 pounds force? Or that it has a mass of 9000 pounds? The tonnage of a ship is the weight of the water it displaces. The force pressing down (normal force) in mechanical problems is significant when friction is involved. Force equals mass time acceleration. So, the mass opposes and increases the force required to get an object moving, or slowed, for that matter. That includes a ship. It has inertia and requires force to change its velocity. Drag is imposed on the submerged portion of the hull, especially when coated with barnacles. I shipped out of Long Beach in WW-2 on the LSM 472. I returned to San Francisco on the LSM 94. I was transferred to the LST 604 to take it up river to Stockton to be decomissioned and scrapped. While at the ship yard there I witnessed a curious sight. A large merchant vessel was moved from one berth to another using a small boat with an outboard motor as the tow boat. River current in the basin was almost nil, yet it took several hours to move that large ship with the power of only an outboard motor. It worked! There must have been nothing more powerful available and there must have been no rush to get the berth swap made. Point is that it is likely that neither mass nor weight is as important as current in many situations. How soon you can get up to speed depends a lot on mass as Newton predicts. That motorboat would have done its thing much more quickly with a waterskier in tow than it did with a big merchant ship in tow. So what is the SI equivalent of those 27,561 tons deadweight for that U.S. Navy ship? Let me open it up to everyone, and make it a multiple choice: 1. 245.19 MN 2. 245.19 hectopascals 3. 2.5003 x 10^7 kg 4. 28.003 Gg 5. 2.1892 x 10^8 newtons 6. 28 003 metric tons 7. 25 003 metric tons force 8. to have five significant digits, it depends on the latitude of the ship 9. all of the above 10. none of the above Does your answer fit in with Richard Harrison's description above? Does it fit with what any shipbuilder or any navy uses? Gene Nygaard http://ourworld.compuserve.com/homepages/Gene_Nygaard/ |
#8
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![]() Gene wrote, On 30 Sep 2003 18:36:50 GMT, (Tdonaly) wrote: Cecil wrote, Gene Nygaard wrote: You can, of course, choose not to call this quantity "weight." You can call it mass instead, if you want to. Here's an interesting quote from _University_Physics_ by Young and Freedman: "On the moon, a stone would be just as hard to throw horizontally, but it would be easier to lift." It also says weight is a vector and mass is a scalar. -- 73, Cecil http://www.qsl.net/w5dxp You better watch out, Cecil, Gene is liable to write a scathing indictment of your intelligence, integrity, and job fitness, for quoting that. By the way, I don't know why I would. I agree with the quoted part. Of course, though the stone is just as hard to throw, it will likely go farther before it falls to the ground. Would you say that a boat is heavy because it is hard to push away from the dock? What is the relevant factor here--that it is pressing down with a force due to gravity of 9000 pounds force? Or that it has a mass of 9000 pounds? What is the metric equivalent of a ton used for the weight of a U.S. Navy ship? For example, the tanker USNS Henry J. Kaiser is 27,561 tons deadweight. How much is that is SI units? Gene Nygaard http://ourworld.compuserve.com/homepages/Gene_Nygaard/ Still playing the old one-note samba are we Gene? You must hold the record for being the most boring guy at the cocktail party. You still haven't answered my question about why you keep harping on a question of elementary physics on a newsgroup devoted to amateur radio antennas. Is this a new species of troll? Is that all you know how to talk about? When did you first realize you had this obsession with mass? Are you over-mass? With the never ending thread about transmission lines, EH antennas, mass, and the rest, it's pretty obvious what has happened. There's been an earthquake; all the pots are cracked. Next, someone from the British Isles will be writing to say gram scales don't MEASURE mass, they only INDICATE mass. Brother. 73, Tom Donaly, KA6RUH |
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