Free fall
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From: Randy Poe on 16 Sep 2005 10:59 Don1 wrote: > Don1 wrote: > > Randy Poe wrote: > > > Don1 wrote: > > > > > > > > These formulas are just adaptations of those found in most basic > > > > physics texts: > > > > > > "Adapted" in that they were changed from correct to incorrect > > > (I missed your error in forgetting to put a "t" after "vi"). > > > > That wasn't an error Randy: There is no t after vi because vi is a > > _ratio_ of length l, to t. The formula in the textbooks is wrong: It > > should be s=(v/i)xt + (a/2)t^2: Dividing all terms by t we should get > > s/t=l/t + (a/2)t > > > My mistake Randy: The formula in the textbooks should be s=(l/t)t + > (a/2)t^2: No, it shouldn't. > Like you told me velocity is a ratio of displacement to time; No, I didn't. If anything, I told you velocity is a rate of change of displacement. Suppose a car is accelerating at a steady 10 m/sec^2, from an initial velocity of 5 m/sec. What are you going to use for l? Show me how you think this formula works to get displacement after 1 sec, 1.5 sec, and 2 sec. The actual answers are: 10 m, 18.75 m, and 30 m. - Randy
From: briggs on 16 Sep 2005 11:16 In article <1126874264.435268.303620(a)g49g2000cwa.googlegroups.com>, "Don1" <dcshead(a)charter.net> writes: > odin wrote: > Snip< >> >> The equation s=(vi)t + at^2 is not found in any textbook unless it is a >> typo. It should be s=(vi)t + (a/2)t^2. > > The equation s=(vi)t + (a/2)t^2 is not found in any textbook that I > know of: The parentheses are mine! I put them around vi, because vi is > a distance l, divided by a unit of time; so that the equation should be > s=(l/t)t + (a/2)t^2. *sigh*. Responding to Don. Note that the t in parentheses is a "unit of time" -- the time interval during which a distance l was traversed. The t outside the parentheses is the elapsed time during which a distance s has been covered. The two t's are entirely separate, distinct and unrelated. Real physicists, mathematicians and people operating with more than half a brain try not to use the same symbol twice in the same equation with incompatible meanings. > The best part is that dividing all terms by t gives s/t=l/t + (a/2)t. > Try that in your peace-pipe. Dividing by t when there are two distinct t's is the fallacy of equivocation. It is an error. It also flies in the face of Don's previous erroneous assertion that "terms" inside of parentheses are indivisible. John Briggs
From: Shmuel (Seymour J.) Metz on 16 Sep 2005 08:38 In <LyVCKjt$mKVu(a)eisner.encompasserve.org>, on 09/15/2005 at 10:21 AM, briggs(a)encompasserve.org said: >Please don't use the term "zero sum game" when it does not apply. It does apply. A non-zero sum game can be converted to a zero sum game by adding an additional player. -- Shmuel (Seymour J.) Metz, SysProg and JOAT <http://patriot.net/~shmuel> Unsolicited bulk E-mail subject to legal action. I reserve the right to publicly post or ridicule any abusive E-mail. Reply to domain Patriot dot net user shmuel+news to contact me. Do not reply to spamtrap(a)library.lspace.org
From: odin on 16 Sep 2005 16:31 >>Please don't use the term "zero sum game" when it does not apply. > > It does apply. A non-zero sum game can be converted to a zero sum game > by adding an additional player. Nope. When you add a player to a game, you change the game entirely. The new game may become zero sum but the old game remains non-zero sum.
From: Bob Cain on 16 Sep 2005 17:29
odin wrote: >>Um... > > > What I am curious about is that Don1 thinks the textbooks are wrong on this > stuff. Yet his equation seems to be different and inconsistent every time he > posts a message about it. God only knows how vi became v/i for no good > reason in this thread. And God only knows what parenthesis actually mean in > his own twisted version of elementary algebra. God only knows why he eschews > calculus, vectors, quantum physics, relativity, etc. I know and I'm not god. It's doubletalk and all the responses to it give him great fun. He couldn't do it so well if he didn't actually know what's going on. The man's an artist and this forum has been his canvas for years. Bob -- "Things should be described as simply as possible, but no simpler." A. Einstein |