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Posted By: ben Posted On: Sep 19, 2006 Views: 1022 | RE: Lunar landings? and before you say it i should probibly work on my spelling :P but hay thats what forums are for :D |
Posted By: Keith Mayes Posted On: Sep 19, 2006 Views: 1021 | RE: Lunar landings? Oh dear. |
Posted By: Bart Posted On: Dec 25, 2006 Views: 1012 | RE: Lunar landings? The only thing that really determines the falldown time is the acceleration, which is equal to the strength of the gravitational field. This acceleration is independant of the mass of the falling object. g = F / m = (G* m * M / (r * r) ) / m = G * M / (r * r) M being the mass of the attracting body (the moon in this case), m being the smaller mass accelerating in the gravititional field. The accelerating mass vanishen from the equation. Of course the larger mass will be attracted to the falling mass by a discardable amount, but again not depending on it's own mass. So in effect, feathers and hammers do hit the ground at the same moment when released at the same height and moment. |
Posted By: Bart Posted On: Dec 25, 2006 Views: 1011 | RE: Lunar landings? Please forgive me. The last alinea is not true, the hammer generating a stronger gravitational field than the feather. It's contribution to the time needed to fall down is however discardable. |
Posted By: Keith Mayes Posted On: Dec 25, 2006 Views: 1008 | RE: Lunar landings? Yes, and as I said in my earlier post the hammer will strike the ground first by the order of a few hundredths of a billionth of a trillionth of a second, if the ground were perfectly flat and level and if it could be measured, which it can't. |
Posted By: Bill Cooper Posted On: Dec 26, 2006 Views: 1006 | RE: Lunar landings? Yeah I know how small the difference is, but it is there, that was my point, however small the differences, mathematically it's there, you couldn't measure it, you would not be able to release the objects at the same time, there will always be a difference, even taking the circumference of the moon in to account [which actually makes the error larger], as does the fact that the feather will accelerate towards the hammer causing it to fall at a slight tangent. Sch minor differences can make a difference, if you believe in the big bang and the initial creation of energy you'll know what I mean, it was minute imbalances that caused the matter to be created. |
Posted By: Terror Firma Posted On: Dec 27, 2006 Views: 1002 | RE: Lunar landings? Idiots! Why waste your time discussing something that never happened? We never went to the moon, only morons like you think we did! |
Posted By: Count Iblis Posted On: Feb 2, 2007 Views: 994 | RE: Lunar landings? The acceleration of the Moon is not the most important effect that will cause a difference in the free fall times. At the Moon's surface there is some gas causing air resistence. The feather may be electrically charged somewhat causing it to emit electromagnetic radiation when falling which will cause it to fall at a slower acceleration. But let's pretend that all these other effects don't exist and focus only on the response of the Moon. When you are holding the hammer in your hands, the hammer exerts a force on the Moon, but your feet are exerting the opposite force on the surface of the Moon. This causes the surface at the place you are standing to be deformed somewhat. Exactly at the moment you release the hammer, the force exerted by your feet on the Moon diminishes. This causes the surface of the Moon to rebound. To find out when the hammer will hit the surface you must solve this initial value problem of an initially elastically deformed Moon. The fact that the center of mass the Moon is also accelerating toward the hammer can be ignored relative to this effect. |
Posted By: Bill Cooper Posted On: Feb 2, 2007 Views: 992 | RE: Lunar landings? Now I wonder what has suddenly bought this topic back to life? Was it perchance the appearance of the article in the Feb edition of the UK Mensa Magazine? Anyway, at the end of the day, assuming perfect condtions (not even a truck passing by on a planet in a nearby solar system) the hammer hits first, by a margin not much wider than a planck width. In practical terms you simply could not build a mechanism to release the two objects at the same instant, let alone measure it. Now suppose your hammer weighs as much as the moon and your feather dropped diametrically opposite, then the feather will have 3 times the distance to 'fall' if initially released from the same height! I say 3 times further but it's a little less than that, by about a couple of planck widths..... |
Posted By: Christopher Posted On: Dec 16, 2007 Views: 942 | RE: Lunar landings? Billy Cooper, The hammer and the feather should hit the moon at the same exact time, not like with a difference of billionths of seconds. However, this is true only for a specific condition: It is when the hammer and the feather are released from the same location at the same instant. Its like releasing the feather from the right hand and the hammer from the left hand, both at the same instant. In this particular case, we do not need to consider the rate at which the moon will be approaching the 2 bodies. This is because the rate at which the moon will be approaching them will be determined by their combined mass ( M1+ M2 ). It is only when the hammer and the feather are released seperately , then we will have this little difference of billionths of a second |
Posted By: Keith Mayes Posted On: Dec 16, 2007 Views: 940 | RE: Lunar landings? That would appear to be a simple yet valid point. The moon cannot approach the two objects at two different speeds. |
Posted By: Christopher Posted On: Dec 16, 2007 Views: 936 | RE: Lunar landings? Wow, the response time of Keith Mayes is 26 -11 = 15 minutes, simply awesome, taking into account how old this thread is. And who is Keith Mayes ?? By the looks of it, i will tend to say . . . Physicist ?? Engineer ?? Mathematician ?? Philosopher ?? |
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