Free fall
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From: Herman Trivilino on 14 Sep 2005 23:57 "Sam Wormley" <swormley1(a)mchsi.com> wrote ... > No you have to start with the differential equation F = ma, and > this time acceleration is not constant.... it is quite a complicated > calculation. Newton gave us all the tools we need. And did all the calculations. And did all that over 200 years ago. And Don is still catching up. Trying to understand what Galileo did over 300 years ago. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =----
From: odin on 15 Sep 2005 01:57 >> > The formula for finding the velocity of free fall is: v = 2s/t; where s >> > is the distance a body falls, and t is the time during which it falls. >> >> Is the moon in free fall? If yes, how does that work with your equation >> above. If not, then what the heck is it doing up there? >> > It's falling, but missing, and passing by: Only to fall back again, and > again. So does the moon obey your equation or not? If not, why not? >> You do not take into account the fact that the force is not constant, but >> depends on displacement (universal gravitation) >> > The gravitation is in the direction of the free fall, and is its cause. But gravitational field strength is not constant, is it? >> Also, even given all these simplifying assumptions, you have an error... >> you have: >> d = vi + (a/2)*t^2 >> you should have: >> d = vi*t + (a/2)*t^2 > > No vi is the point of beginning; the rate of the initial _inertial_ > displacement l: It is equal to l/t; for vi = 0, it is 0/t. Nope. The variable vi is the initial velocity. If you do not multiply it by t, you will fail in your dimensional analysis. If vi = 10 miles/hour, and t = 2 hours, assuming for now that a = 0 (like in deep space), doesn't it make sense that after t, the displacement would be vi*t or 10 miles/hour * 2 hours to give you 20 miles?
From: Eric Gisse on 15 Sep 2005 02:39 odin wrote: [snip] Please, please, please stop validating his existance. The zero sum game of trying to teach Don anything needs to stop.
From: Timothy Little on 15 Sep 2005 05:43 Eric Gisse wrote: > Please, please, please stop validating his existance. The zero sum > game of trying to teach Don anything needs to stop. Zero-sum? And here was I thinking it was negative-sum. - Tim
From: Don1 on 15 Sep 2005 08:21
Randy Poe wrote: > Don1 wrote: Snip< > > Using these simple formulas it is possible to find the velocity and > > distance a body free falls during any period of time. > > Yes, if correctly applied. This is the most correct post I've seen > from you but there is still a slight misinterpretation of the > meaning of the formulas. > > - Randy These formulas are just adaptations of those found in most basic physics texts: With further adaptions they will apply to all kinds of motion. You, or someone who will make the effort, and has the fortitude, could be the one to do it. I'm running out of time and energy now but have made substantial inroads which as time and energy permit, I'll be continuing to persue. Don |