## View Poll Results: The falling hammer and feather in perfect conditions.

Voters
51. You may not vote on this poll
• The hammer would strike first

19 37.25%
• The feather would strike first

0 0%
• They would strike at the same moment

32 62.75%

# Thread: Which hit first the hammer or the feather?

1. I long ago concluded if the hammer and feather were dropped at different times the hammer would take the least time to contact the moon's surface, since the moon would also be attracted to the hammer, and the mass of the hammer is larger than the mass of feather ergo the combined acceleration would be greater when the hammer was released.

I have also managed to prove (or should I say convince) myself that if dropped at the same time the hammer would also hit first, especially if the moon were a perfect sphere and had uniform density throughout.

Before I offer the proof, would anyone agree with me - no matter how minute the difference in time is?

2.

3. Hell NO
they will fall at the same speed, im going to prove why by using hte formulas newton used

F=m<sub>2</sub>a
F=Gm<sub>1</sub>m<sub>2</sub>/r²
m1 is the mass of the moon, m2 is the mass of the second object
therefor
a=Gm<sub>1</sub>/r²
we get rid of m2 on both sides
oh well i be damn, it doesnt matter what mass the second object has, it will fall at the same rate. So please dont try this, its elementary knowledge that everything fall at the same rate aslongest not other forces are involved

4. Originally Posted by Zelos
Hell NO
they will fall at the same speed, im going to prove why by using hte formulas newton used

F=m<sub>2</sub>a
F=Gm<sub>1</sub>m<sub>2</sub>/r²
m1 is the mass of the moon, m2 is the mass of the second object
therefor
a=Gm<sub>1</sub>/r²
we get rid of m2 on both sides
oh well i be damn, it doesnt matter what mass the second object has, it will fall at the same rate. So please dont try this, its elementary knowledge that everything fall at the same rate aslongest not other forces are involved
The maths you have so elequently shown shows only the tendency of the object to move toward the moon. You have NOT shown that the moon will also move toward the hammer giving combined acceleration. Now is there any intelligent life in this forum or is it just like all the others and full of morons! - with apologies to anyone out there who really understands science.

5. well you obviusly cant your math
in F=m<sub>2</sub>A
you can replace m<sub>2</sub> (wich is the amss of the object) with m<sub>1</sub> , the mass of the moon, you get the same thing

of course if you take this into considiration that becuase mooon also accelerates it will spend less time then i want you to go to the beach, take a wiss into the ocean then measure the ocean level differens caused by your pee

astronaughts on apollo 17 or 15, who cares.
did this experiment, and the hammer and the feather both contacted the ground at the same time.

experimental science.

7. yes, gallileo also proved it on earth, and newton proved it mathematical

8. Originally Posted by Zelos
Hell NO
they will fall at the same speed, im going to prove why by using hte formulas newton used

F=m<sub>2</sub>a
F=Gm<sub>1</sub>m<sub>2</sub>/r²
m1 is the mass of the moon, m2 is the mass of the second object
therefor
a=Gm<sub>1</sub>/r²
we get rid of m2 on both sides
oh well i be damn, it doesnt matter what mass the second object has, it will fall at the same rate. So please dont try this, its elementary knowledge that everything fall at the same rate aslongest not other forces are involved
I think you are missing his point. Clearly the hammer and the feather will both experience the same acceleration toward the moon's center of gravity. However, billco is arguing that the moon will also experience a slight acceleration toward the center of mass of the dropped object due to the gravity of the dropped object. Since the hammer is more massive than the feather, the hammer will accelerate the moon toward its center of gravity slightly faster than the feather will accelerate. In your math above you calculated the acceleration of the dropped object and assumed that the moon would remain stationary, which isn't quite correct. To get an exact answer you would need to calculate the acceleration of both the dropped object toward the moon and the moon's acceleration toward the dropped object.

I believe he is correct. Obviously the difference will be very small, but it would be non-zero.

However, this part of his claim is wrong:
I have also managed to prove (or should I say convince) myself that if dropped at the same time the hammer would also hit first, especially if the moon were a perfect sphere and had uniform density throughout.
This is wrong because if you dropped both at the same time, the moon would accelerate toward the combined center of gravity for the hammer and feather. Both would strike slightly sooner than either would have if dropped by itself, but they will strike at the same time.

9. Originally Posted by Zelos
of course if you take this into considiration that becuase mooon also accelerates it will spend less time then i want you to go to the beach, take a wiss into the ocean then measure the ocean level differens caused by your pee
billco made exactly this point in his opening post.
Originally Posted by billco
Before I offer the proof, would anyone agree with me - no matter how minute the difference in time is?
Please refrain from attacking people in this way, especially when they have made a perfectly valid point.

Thanks to scifor for examining the issue dispassionately in a scientific manner.

Originally Posted by billco
Now is there any intelligent life in this forum or is it just like all the others and full of morons!
We can do without the generic ad hominems (or the specific for that matter). Provocation is not a justification.

10. Ophiolite, i wasent attacaking him, i told him what to do, its the same principle. If he can measure any differens in the water level then there is worth thinking of this differens aswell. My point is qutie simple. the

differens here is insignifican. Peeing in the ocean is a good exemple of insignifican addition/differens or what ever, it isnt measurble

11. Woops, upon further consideration I have to change my opinion on the last part of my post. If you assume that the moon is a perfect sphere of uniform density (as billco stated in his post) then the hammer would indeed strike first if you dropped both at the same time, since the center of gravity for the hammer/feather system would be closer to the hammer than the feather. This would move the center of gravity for the entire moon/hammer/feather system slightly closer to hammer than to the feather, so the hammer wouldn't have to travel as far as the feather before it hits. Looks like billco was right all around.

12. its insignifican. like 10<sup>-23</sup>
think it is nuclear time scale we are tlaking about

13. Originally Posted by Zelos
Ophiolite, i wasent attacaking him, i told him what to do, its the same principle. If he can measure any differens in the water level then there is worth thinking of this differens aswell. My point is qutie simple. the

differens here is insignifican. Peeing in the ocean is a good exemple of insignifican addition/differens or what ever, it isnt measurble
It seems likely that you didn't understand what he was saying in his original post, since the mathematical "proof" that you offered completely ignored his entire point, which was that the moon will also accelerate slightly. In his original post he asked if anyone would agree with him "no matter how minute the difference in time is". Although the difference is small, it is non-zero, so he is correct.

14. when u can measure that amount its significan to calculate

15. He didn’t ask “is there a difference that can be measured”. He asked if there was any difference “no matter how minute”. I can’t believe you are so reluctant to admit that you were wrong. Heck, I was wrong about something in my original post too.

Of course, I didn’t act like an arrogant jackass by saying things like "it's elementary knowledge" or "you obviously can't do math", so maybe that’s why it’s easier for me to admit that I made a mistake.

16. I can’t believe you are so reluctant to admit that you were wrong.
Of course, I didn’t act like an arrogant jackass by saying things like "it's elementary knowledge" or "you obviously can't do math", so maybe that’s why it’s easier for me to admit that I made a mistake.
i´ll let this pass by the assumption you are new. look throu the forum and you will see i have admited to be wrong many many times, i admit it i can be wrong, and if i have insulted someone and is wrong i apologise, im not those losers who cant apologise or say im wrong.

bieng wrong is a part of bieng human, aslongest im human i´ll admit bieng wrong when i am wrong.

17. Zelos, you were wrong, billco was right.

End of story. Please accept this so we can all move on. Don't nitpick about whether or not it is measurable. billco didn't put that restriction on it, just a discussion of whether the effect was there or not.

Scifor, thank you for revising your view on the hammer striking first. I wondered about that when you said it was wrong, but my head gets wrapped in knots when I try thinking about such matters. (My maths is stuck at the level of a four year old genius. )

18. end of story? sorry but i just went crazy so i´ll continue
, now iamgen a 500 pages explination why im right with alot of wrong formulas here

i think by just saying its insignifican differens says "tere is a differens but it is insignifican"

19. Thankyou Scifor,

It is nice to see there are some who are open to change their initial belief by rational argument. I was careful as you correctly pointed out in my choice of words. You are sir, a credit. Now I hope you win as many bets as I have over the years on this one.

It is also nice to see at least one forum which has a percentage of genuine contributors, do you mind if I make this my home forum?

Rgds BC.

20. Originally Posted by billco
It is also nice to see at least one forum which has a percentage of genuine contributors, do you mind if I make this my home forum?
Delighted.

21. i have to admit thou, that billco got a insignifican point

22. dont the moon gravity affect their acceleration? o.O that wat i think

23. Originally Posted by Zelos
i have to admit thou, that billco got a insignifican point
I'll take that as a compliment, and bid you good day sir, may the seed of your loin bear fruit in the belly of your woman, and may you live to conquer many more planets.

"Those who cannot adapt shall, like the dinosaurs, not survive" Billco

24. that last thing is the thing you have said that make the most sense i have heard yet

25. Originally Posted by Scifor Refugee
However, billco is arguing that the moon will also experience a slight acceleration toward the center of mass of the dropped object due to the gravity of the dropped object. Since the hammer is more massive than the feather, the hammer will accelerate the moon toward its center of gravity slightly faster than the feather will accelerate. In your math above you calculated the acceleration of the dropped object and assumed that the moon would remain stationary, which isn't quite correct. To get an exact answer you would need to calculate the acceleration of both the dropped object toward the moon and the moon's acceleration toward the dropped object.
If this were the case, there would be warps all over from the moon accelerating at different rates.

I don't know much about gravity or physics, but this all sounds a little crack-potty to me... :?

J0N

26. Jon (quote) "I don't know much about gravity or physics, but this all sounds a little crack-potty to me... (unquote)

If you know anyone (personally) who has a grasp of these matters, why not print out the whole of this thread, present it to them and ask for their opinion? or ask them to view the thread online and perhaps contribute?

Or work it out for yourself? although it sounds very complicated it's just a bit of algebra, formula translation, and a bit of trig chucked in. There's no calculus, I have simply used the most widely understood maths to make a point that other ordinary folk (like myself) can grasp. Using 'advanced' mathematics would merely be showing off and, completely inappropriate to a forum where people come to learn about science and not be 'blinded by it'.

As a final point Jon NOBODY understands gravity, we just have a handful of formula to explain the effect we see - so you are NOT alone there!

27. YES, the moon will also accelerate toward the hammer. BUT this will happen with such a neglectable intensity that science considers that hammer and feather impact at the same time.

28. The Sun pulls the planets and they pull the Sun and each other. Same goes for the hammer and the moon. The Universe doesn't suddenly decide it can't be bothered because the hammer's mass is too insignificant compared to the moon's mass.

29. The discussion (as has already been said) was about whether there was a difference - 'no matter how insignificant' - that as far as I am concerned has ben concurred with by others after considered thought.

It is the discovery/explanation of error which leads to the advancement of science.

The difference is of a similar order of magnitude as was found when the two atomic clock test was done to prove/dispprove part of Einsteins theory ie one on the ground the other in a plane. in science NO difference (if repeatable and not variation of error) however small is insignificant.
We do NOT say "Oh well the difference is so small we will ignore it".

Another such was:

Minute amount of background noise in a receiver:

[extracted from full text at] http://www.bell-labs.com/project/fea...ves/cosmology/

[The discovery in 1963 by Arno Penzias and Robert Wilson (Nobel Prize winners) of the cosmic microwave background of the Big Bang set the seal of approval on the theory, and brought cosmology to the forefront as a scientific discipline. It was proof that the universe was born at a definite moment, some 15 billion years ago.]

This particular anomaly was believed to have been noticed earlier, however it was not at that time investigated, it was ignored.

So come on guys, I encourage you to find such anomolies - and you could find a place in history.

30. I don't know - I definitely see the point that most agree with in this thread, but I'm not convinced that the hammer hits first by any margin whatsoever.
The hammer may pull the moon a small amount, but it's being pulled both toward the hammer, and the feather as they're falling from almost the same angle. The only difference is the horizontal direction, and the only way that would impact which hit first is if the curvature of the moon is significant enough that the sideways motion towards the hammer, and away from the feather, is enough to be the difference. I think at a size scale of hammers and feathers the moon is effectively flat. The question in my mind is how continuous is the moon's curvature - if it's somewhat continuous I'd agree the hammer strikes first by the smallest of margins. However, if over small distances the moon is actually "flat" and the curvature takes place at more discreet intervals, I don't agree that the hammer would strike first.
I'd certainly entertain the idea that I'm wrong, but why am I?

31. Originally Posted by Neutrino
The question in my mind is how continuous is the moon's curvature - if it's somewhat continuous I'd agree the hammer strikes first by the smallest of margins.
Like he said, you have to assume that the moon is a perfect sphere.

32. Originally Posted by Neutrino
I don't know - I definitely see the point that most agree with in this thread, but I'm not convinced that the hammer hits first by any margin whatsoever.
Ok I can accept your reluctance to accept something that appears to fly in the face of that which you have held true. Especially from an apparently 'unknown' person - I would too, unless I could see and understand the proof. Perhaps you might like to shelve this one for a while and maybe you will see the argument clearer with time. Maybe even come back and say "at that level you are correct but there is something else you have missed.." (I'm not aware I have, having done the Calcs to a very fine level - including even the attraction of the hammer and feather to each other as well as to the centre of the moon.)
For my calculations I used a hammer of mass 10.001 Kilos and a feather of 0.001 kilos A drop height of 1.5 Metres, Seperation (Hammer to feather of 1Metre) I used 7.36 * 10^22 kilos for the moon mass and 1738KM for the radius of the moon. As a matter of note I discovered this whilst producing a general formula for Horizon distance on any body.
(A simple trig function it turns out to be).

33. The basic logic of the idea is correct, without question. But, the amount would be so insignificant that a question to ask might be whether it would even occur or not.

Might this difference be below a threshold such as the planck length where it's either all or nothing?

Another point to make is that the hammer and feather would not fall as a unique event. There was a history to the hammer and the feather being in the position they are in. This history would also have affected the position of the moon (assuming that such things are above the threshold posited in point one above.) I suspect that the grand total of all such hammer/moon/feather interactions would somehow cancel out this insignificant factor. At least somewhat.

Also.
You've gone part of the way towards thinking from all perspectives but have forgotten a few.

The hammer's attraction to the feather and vice versa.

Let's also not forget the body of the astronaut dropping the hammer and the feather.

All in all, with all possibilities accounted for, the equations quickly become quite untenable...
Or so I should think.

34. Wouldn't the atmospheric drag affect the result too? (and before anyone says that the moon doesn't have an atmosphere i'd like to remind you that it does, it's just very... what's the opposite of dense? i've completely forgotten... thin? not quite right, but it'll do).
I don't have the patience for doing the calculations. And it's a while since i did any physics. So i'm sorry if i've missed something blindingly obvious here.

35. Sheesh billco I understand the argument. Did you read my post? You're addressing me as if you hadn't. I think Skin's reply to me was a relevant one but I'm not sure what to do with yours.

36. Originally Posted by invert_nexus
The basic logic of the idea is correct, without question. But, the amount would be so insignificant that a question to ask might be whether it would even occur or not.

Might this difference be below a threshold such as the planck length where it's either all or nothing?
I doubt it. Planck length is on the order of 10^-35 m. The distance difference here would be around the order of 10^-23 meters, so you're still talking somewhere around a trillion times more than Planck length.

37. The distance difference here would be around the order of 10^-23 meters
How'd you come up with that particular value?

38. Originally Posted by Neutrino
Sheesh billco I understand the argument. Did you read my post? You're addressing me as if you hadn't. I think Skin's reply to me was a relevant one but I'm not sure what to do with yours.
I have read and understood as much of your posts as you have of mine.

Unless anyone can demonstrate with a proof (using Newtinian mechanics and simple trigonometry) that I am incorrect I see no point in continually adding to this thread.

Now can we please move on?

39. is anyone else sick of learning counter intuitive information or information that contradicts earlier teachings?

i know i am.

40. Originally Posted by Neutrino
How'd you come up with that particular value?
Woops, I made a mistake there. 10^-23 is about the time difference in seconds between when the hammer would hit and when the feather would hit, not the distance difference. I calulated the acceleration due to gravity for the moon falling toward a hammer that massed 1 kg. The distance that the feather had left when the hammer hits would only be something like 10^-29 meters.

41. Originally Posted by Scifor Refugee
Originally Posted by Neutrino
How'd you come up with that particular value?
Woops, I made a mistake there. 10^-23 is about the time difference in seconds between when the hammer would hit and when the feather would hit, not the distance difference. I calulated the acceleration due to gravity for the moon falling toward a hammer that massed 1 kg. The distance that the feather had left when the hammer hits would only be something like 10^-29 meters.
Well, in a simultaneous drop most of the motion of the moon towards the hammer is also going towards the feather, is it not? Did Billco's, or your, calulcations incorporate this? Further, how do either of you know exactly how the motion of the moon will be affected? Were you considering everything as a point particle, or figuring out how they might rotate? Would the center of mass of the moon move directly towards the center of mass of the hammer + feather with no rotation? Or would the hammer + feather cause the moon to rotate slightly(or both)? How do you know? Aren't these little details important? Without figuring out a little bit more of the picture I'm just not 100% convinced. If you are considering everything as a point particle and just changing the masses, I'd probably agree. But the post is about a hammer, a feather, and a moon.
It seems to me that the position from which you drop the hammer and the feather, and the resultant rotation of those 2 objects, would have a greater impact on which hits first than the pull of the those objects on the moon would.

I have read and understood as much of your posts as you have of mine.

Unless anyone can demonstrate with a proof (using Newtinian mechanics and simple trigonometry) that I am incorrect I see no point in continually adding to this thread.

Now can we please move on?
Well it's hard to say, since you haven't posted your work. Were you going to post them? I mean my guess is that you're probably right but from what I've seen, I'm not convinced.

42. The feather would OBVIOUSLY fall first. Feathers come from animals, which were created by god. Hammers were created by man. Thus, god would give the feather the upper hand and it would land first.

J/k lol :P

Neutrino has a very strong point in my humble opinion. Any difference in the fall could easily be overidden by quantum mechanical fluctuations or rotation of the bodies. One must also define what you mean by "hit". On the scales you are considering, the idea of "touching" becomes very very ambiguous. Also, cosmic rays could build up a charge/current in the metal of the hammer, causing different amounts of repulsion. Also, the cosmic rays would induce more motion in the feather due to its smaller amount of mass and greater exposed area. IMHO there is just to much other information to worry about to figure out differences on the scale of 10<sup>-29</sup>.

43. Perhaps this topic has been beat to death, but here are my 2-cents...

Possibly a better way to ask the question would be;

You have a mass m1 at rest a distance r away from (the center of) a much larger mass M also at rest. You let them move towards each other under only their mutual gravitational force and calculate the time it takes for them to collide (or not collide, but rather move a specified distance... and actual values are arbitrary as long as you are consistent throughout the calculation)...
Then you replace the mass m1 with a smaller (or larger) mass m2 and repeat the calculation (or thought experiment, or what-have-you) with all else remaining the same.

Will the collision times be equal, or will one be greater than the other?

Of course, asking the question in this manner is not the best way to ask it if you want to sucker \$ out of someone....

But... this has the beauty of allowing arbitrary values (especially masses). Either the collision time will be mass-dependent or not. If it turns out to be mass-dependent (dependent on m and M that is), then one of them will hit first.

If I were going to attempt the calculation, since we are only concerned with the "collision" time, I would simply solve the two-body problem for the collision time of two point masses m and M separated by a distance r. If m is in the result, then one of them will hit first (which one (i.e., the hammer or feather) depends on how the result depends on m). And since we are interested in the dependence on the smaller mass, m, make sure not to use the approximation m << M.

(Edit): Actually, the approximation m << M is valid for Galileo's experiment, which is why he got the result he did.... (end edit)

I encourage you all to do this calculation. It turns out that m is in the answer....

Cheers,
william

44. you could also say that noone of them hit the moon first. they both hit at the same time. the feather and hammer contain many many electrons and the chance of one of those electrons hitting the surface at the same time do i guess is rater high. so accoriding to this we have a tie

45. Originally Posted by william
Perhaps this topic has been beat to death, but here are my 2-cents...

Possibly a better way to ask the question would be;

You have a mass m1 at rest a distance r away from (the center of) a much larger mass M also at rest. You let them move towards each other under only their mutual gravitational force and calculate the time it takes for them to collide (or not collide, but rather move a specified distance... and actual values are arbitrary as long as you are consistent throughout the calculation)...
Then you replace the mass m1 with a smaller (or larger) mass m2 and repeat the calculation (or thought experiment, or what-have-you) with all else remaining the same.

Will the collision times be equal, or will one be greater than the other?

Of course, asking the question in this manner is not the best way to ask it if you want to sucker \$ out of someone....

But... this has the beauty of allowing arbitrary values (especially masses). Either the collision time will be mass-dependent or not. If it turns out to be mass-dependent (dependent on m and M that is), then one of them will hit first.

If I were going to attempt the calculation, since we are only concerned with the "collision" time, I would simply solve the two-body problem for the collision time of two point masses m and M separated by a distance r. If m is in the result, then one of them will hit first (which one (i.e., the hammer or feather) depends on how the result depends on m). And since we are interested in the dependence on the smaller mass, m, make sure not to use the approximation m << M.

I encourage you all to do this calculation. It turns out that m is in the answer....

Cheers,
william
This is nice, but too abstract for the problem. We are asking about a hammer and a feather and a celestial body, not three point masses.

46. Vroomfondel wrote:
This is nice, but too abstract for the problem. We are asking about a hammer and a feather and a celestial body, not three point masses.
I agree.
But ironically, I can't think of a simpler way to actually do the problem (that is, get a definite answer as opposed to mere speculation).

You've mentioned you'll be entering the collegiate world of physics in a couple years... you'll see this sort of approximation is done all the time.

There's a joke that starts out something like this;
"Why did the chicken cross the road?... Well, we first have to assume a spherical chicken... ." I love that one!

There's always the real problem, and then the tractable one....

Cheers,
william

47. "Those who can solve the problem have done so, those who cannot, seek only to muddy the waters and convince others of the insolubility of the problem" - anon.

48. Billco wrote:
"Those who can solve the problem have done so, those who cannot, seek only to muddy the waters and convince others of the insolubility of the problem" - anon.
On the contrary billco, the waters are clear now, and a careful reading of my post should lead you to the interpretation that I agree with your assessment of the solution. I only provide one way in which a physicist (a more abstract approach), as opposed to an engineer (a more concrete approach), would go about finding the solution. And I stress, there is nothing wrong with any method as long as it provides the correct solution. The methodology I propose shouldn't muddy the waters but actually clear them. And I am far from proposing the insolubility of the problem - I actually provided a solid way in which to solve it. It is fairly straight forward. Physics 101.

Your original question was fine. It inspired debate and discussion. Think of my post as simply an addendum to yours. My post is the way I would interpret your original question so as to perform the calculation.

Cheers,
william

49. Originally Posted by william
Billco wrote:
"Those who can solve the problem have done so, those who cannot, seek only to muddy the waters and convince others of the insolubility of the problem" - anon.
On the contrary billco, the waters are clear now, and a careful reading of my post should lead you to the interpretation that I agree with your assessment of the solution. I only provide one way in which a physicist (a more abstract approach), as opposed to an engineer (a more concrete approach), would go about finding the solution. And I stress, there is nothing wrong with any method as long as it provides the correct solution. The methodology I propose shouldn't muddy the waters but actually clear them. And I am far from proposing the insolubility of the problem - I actually provided a solid way in which to solve it. It is fairly straight forward. Physics 101.

Your original question was fine. It inspired debate and discussion. Think of my post as simply an addendum to yours. My post is the way I would interpret your original question so as to perform the calculation.

Cheers,
william
My comment was not directed at you, it was directed at all those who tried to throw in such irrelevances as Planck's constant, the color of the wind, etc. You are intelligent enough to know what I am saying - doubtless you have seen post's yourself that raise incredulity. I try as I have always done to get people to look and discover things for themselves, not just take other peoples word for it. As I have said before it is the discovery and exploitation of minor errors that moves science forward - As Einstein did to Newton (re-Mercury orbit discrepency).

If you were originally of the thought that the hammer and feather would strike together and now you have decided the hammer may strike first,
then I am happy.

Cheers.

50. Are we entirely sure that NO GASES are present on the moon to cause resitance, which would slow the feather more than the hammer in the same way as wind resistance.

51. Originally Posted by AJ72
Are we entirely sure that NO GASES are present on the moon to cause resitance, which would slow the feather more than the hammer in the same way as wind resistance.

52. There is an atmosphere, but it is incredibly rarified. I don't believe its existence was recognised until quite recently (post Apollo).

It's drag effect on the feather would be very small, but then so are the other effects that are being considered in this thread.

53. Billicus is clearly a psychiatric condition tipified by taking things, particularly oneself, far too seriously. This was hardly a serious thread, as stated early on: Galileo :? sort of covered this I beleive, and the effect of the differing mass of the falling (well, rolling) objects he observed would have raised precisely the same question, by this far into an "obvious answer post", it's a shame to have to employ smilies when being tounge in cheek.

54. Seriously? Same time.

55. The feather might appear to land first , as the hammer might bounce.
Of course, the feather might bounce, and the hammer not, which wouldappear to back up the hammer theory. So much to consider.

56. Nah THe Hammer hit's first we all know that now but the margin is so tiny.
For all practical purposes they hit at the same time, however precise mathematics shows the hammer hits first.

57. Originally Posted by billco
For all practical purposes they hit at the same time, however precise mathematics shows the hammer hits first.
Can you refer me to the post where you demonstrated this, and also detailed which factors you took into acount and what the starting conditions are? Thanks

58. Originally Posted by Neutrino
Originally Posted by billco
For all practical purposes they hit at the same time, however precise mathematics shows the hammer hits first.
Can you refer me to the post where you demonstrated this, and also detailed which factors you took into acount and what the starting conditions are? Thanks
It's all back in the thread I'll summarise.

Hammer 10.0001Kg, Feather=0.1gms
Moon Perfectly Spherical - uniform density throughout.
Test in 100% vacuum, no other mass's around to 'upset the experiment'

As well as the moon attracting the hammer the hammer will attract the moon (thus BOTH MOVE) - same with feather.

IF each were dropped seperately Hammer would hit moon first as the moon would move toward the hammer faster than it would toward the feather.

When you drop both the moon will be attracted to the common centre of gravity of the hammer & feather system, If the hammer has more mass the moon will therefore tend towards the hammer. From this the hammer will fall to the closest part of the moon's circumference. The feather can only fall further around the moon and therefore has further to travel.

Please note I am NOT contradicting anybody - Newton only indicated they would accelerate at the same rate toward the moon, that was and is true. Incidentally the feather will also fall towards the hammer making it's path longer anyway.

59. well well well, it seems the purveyor of Time Domain Radiospectrawhatever has a scientific theory of his own.

Im delighted to tell you that indeed you are right, indeed the hammer will hit the moon first. Please excuse me while I cover my laughs about how tortured some of you have been in arriving at this conclusion, and I hope billco, that this isn't the pinnacle of your scientific endevour.

While I smirk about the level of narrow minded fundamentalism thats gone on. Let me tell you what you people lack. Vision and imagination. Call yourself scientists? I've seen more enlightenment over at Answers in Genesis.

Let me tell you that the solution to this problem is no harder than a 5 second mental excercise. God knows why you were unsure enough about your proof billco to warrant a thread on it.

So anyway, here is the proof to those of us with functioning brains. No math required.

Picture this in 2 dimensions.
Position the hammer directly to the left of the moon, position the feather an equal distance to the right. The moon being perfectly in the centre. Let go of the hammer and feather at exactly the same time. All things being equal and perfectly dense and spherical, the gravitational attraction on moon from the hammer will be greater than that of the feather, so the moon will move towards the hammer more than iot does towards the feather - so the feather will have a greater distance to travel than the hammer to hit the moon. So the hammer hits first.

60. Originally Posted by marcUK
well well well, it seems the purveyor of Time Domain Radiospectrawhatever has a scientific theory of his own.

Im delighted to tell you that indeed you are right, indeed the hammer will hit the moon first. Please excuse me while I cover my laughs about how tortured some of you have been in arriving at this conclusion, and I hope billco, that this isn't the pinnacle of your scientific endevour.

While I smirk about the level of narrow minded fundamentalism thats gone on. Let me tell you what you people lack. Vision and imagination. Call yourself scientists? I've seen more enlightenment over at Answers in Genesis.

Let me tell you that the solution to this problem is no harder than a 5 second mental excercise. God knows why you were unsure enough about your proof billco to warrant a thread on it.

So anyway, here is the proof to those of us with functioning brains. No math required.

Picture this in 2 dimensions.
Position the hammer directly to the left of the moon, position the feather an equal distance to the right. The moon being perfectly in the centre. Let go of the hammer and feather at exactly the same time. All things being equal and perfectly dense and spherical, the gravitational attraction on moon from the hammer will be greater than that of the feather, so the moon will move towards the hammer more than iot does towards the feather - so the feather will have a greater distance to travel than the hammer to hit the moon. So the hammer hits first.
They don't have to be on opposite sides, then can be right next to each other!

Oh very good, I was never unsure of it. as you say a 5 second thought.
I have other theories as well - you have to remember these guys are just ordinary folk - all I do is try to get them to think outside the box - just like what you iz doing when you come up with your theory. No it is not the pinnacle of my endeavour. I am a retired physicist (radio & electronics). The pinnacle of my career was the re-design of a part of the Space Shuttle System. Not I hasten to add, the O-rings. I joined this forum to try and pass a few things on before too many more of my faculties fail and I cease to be.

61. Originally Posted by billco

They don't have to be on opposite sides, then can be right next to each other!
precisely - you dont need to explain that to me Take things to extremes - makes things clear and simple.

Originally Posted by billco
Oh very good, I was never unsure of it. as you say a 5 second thought.
I have other theories as well - you have to remember these guys are just ordinary folk - all I do is try to get them to think outside the box - just like what you iz doing when you come up with your theory. No it is not the pinnacle of my endeavour. I am a retired physicist (radio & electronics). The pinnacle of my career was the re-design of a part of the Space Shuttle System. Not I hasten to add, the O-rings. I joined this forum to try and pass a few things on before too many more of my faculties fail and I cease to be.
ok, all square! nice to meet you - maybe i'll stick around, i could probably learn a few things off you

62. So if you are going to treat them as point masses, why is the thread about a hammer and a feather?

63. If Galileo had called it 'The three point mass conundrum' then so would I.

64. Originally Posted by Neutrino
So if you are going to treat them as point masses, why is the thread about a hammer and a feather?
It's just a simple way to get the answer.

Cheers,
wm

65. Originally Posted by william
Originally Posted by Neutrino
So if you are going to treat them as point masses, why is the thread about a hammer and a feather?
It's just a simple way to get the answer.

Cheers,
wm
Actually I called it the hammer and feather so people would automatically identify with it - most must have heard of it.

And I know that is the correct answer, cos it's my thread!

66. Originally Posted by billco
And I know that is the correct answer, cos it's my thread!
I'll have to remember that one :P

67. Billco: I'm not sure you could justify this as an "anomaly" because your conclusion is based purely on the theoretical evidence. Real anomalies have to be measured experimentally. Almost by definition an anomaly is something that doesn't fit your model, anything that is predicted by your model is thus not an anomaly.

In fact if we were to conduct the experiment in a perfect way and found that the hammer and the feather actually do hit the ground at precisely the same moment, then that would be an anomaly.

Also, your whole argument rests purely on the validity of the Newtonian model.

68. Originally Posted by billiards
Billco: I'm not sure you could justify this as an "anomaly" because your conclusion is based purely on the theoretical evidence. Real anomalies have to be measured experimentally. Almost by definition an anomaly is something that doesn't fit your model, anything that is predicted by your model is thus not an anomaly.

In fact if we were to conduct the experiment in a perfect way and found that the hammer and the feather actually do hit the ground at precisely the same moment, then that would be an anomaly.

Also, your whole argument rests purely on the validity of the Newtonian model.
What makes you think I am trying to justify an anomaly?
More specifically, what anomaly?
I have not used that word, in this thread, in connection with the hammer and feather.

69. they don't fall but stay right where they are until something hits them. if their perfect conditions let go at same time same place then intertia says they stay.

70. At the end of your post near the bottom of page 2 you said:

"So come on guys, I encourage you to find such anomolies - and you could find a place in history."

By the tone of your little speech I inferred that you were referring to your "findings" as an anomaly. Perhaps I was too hasty?

71. My high-school level physics knowledge are limiting me on this one. I've scanned through the posts and there's one thing I don't understand:

Originally Posted by billco
...if the moon were a perfect sphere and had uniform density throughout.
How does this effect things? I can understand how the hammer pulls on the moon more than the feather, so there would be a microscopic difference in the time they hit, but what does the shape of the moon have to do with it?

Another question: if I dropped my ex-girlfriend and a hammer off a cliff at the same time, which one would hit first?

72. I realised that I did not participate to this wonderful Billco's thread.
So here is my grain of salt.

I am a bit surprised that nobody here mentionned an important point : the hammer is rigid, the feather is not.
What will happen if the feather slighty change of shape while diving ?
For example let admit, that the feather become more incurvated, and that this incurvation face the moon. If the feather both fall and both incurvate, she might touch the moon before the hammer.

73. Originally Posted by Powerdoc
I realised that I did not participate to this wonderful Billco's thread.
So here is my grain of salt.

I am a bit surprised that nobody here mentionned an important point : the hammer is rigid, the feather is not.
What will happen if the feather slighty change of shape while diving ?
For example let admit, that the feather become more incurvated, and that this incurvation face the moon. If the feather both fall and both incurvate, she might touch the moon before the hammer.
yes, and look at intertia. it would only work if it had effect of a cause.

74. Originally Posted by Powerdoc
I realised that I did not participate to this wonderful Billco's thread.
So here is my grain of salt.

I am a bit surprised that nobody here mentionned an important point : the hammer is rigid, the feather is not.
What will happen if the feather slighty change of shape while diving ?
For example let admit, that the feather become more incurvated, and that this incurvation face the moon. If the feather both fall and both incurvate, she might touch the moon before the hammer.
Doc the feather is made if tungsten steel. The hammer is made of rubber,the Hammer'a mass is 10.0001Grammes and the feather 0.1 Grammes

75. Originally Posted by billco
Originally Posted by Powerdoc
I realised that I did not participate to this wonderful Billco's thread.
So here is my grain of salt.

I am a bit surprised that nobody here mentionned an important point : the hammer is rigid, the feather is not.
What will happen if the feather slighty change of shape while diving ?
For example let admit, that the feather become more incurvated, and that this incurvation face the moon. If the feather both fall and both incurvate, she might touch the moon before the hammer.
Doc the feather is made if tungsten steel. The hammer is made of rubber,the Hammer'a mass is 10.0001Grammes and the feather 0.1 Grammes
,1 gramme for a tungsteen steel feather : it must be extremely small : D

What kind of birds is wearing such feathers ?

PS : I also expect that both the hammer and the feather are not subject to magnetic forces

76. Shouldn't you be over in biology helping out.........

77. I think that you clearly demonstrated gravity work both way, and that some people have forgotten this point, because as the mass of the feather is negligeable, it's not taken in account. This is a simplification.

Calculating the attraction in both direction and strenght recquieres at first to caclulate the barycentre of the differents masses in presence minus the one you want to calculate the attraction. This work for any system regardless of the number of elements.

I just wanted to remind you, that when you give "real life" examples, in order to make the problem more human friendly, you tend to introduce others factors, such a solar wind, meterorites, magnetic field, dilatation ...

78. Change the objects to a hammer and a feather dropped on a tiny moon of say ten hammer masses. And make it a moon very low density and high surface area; say ten square miles of surface area so the hammer and feather could be dropped at the same time at a distance of 100 ft. apart.

This way, the hammer will pull the tiny moon more noticeably.

This should help make the answer more obvious; the hammer.

Oops. I just noticed that there were six pages of posts on this thread and I only read the first page. Probably my suggestion has already been made.

79. Originally Posted by bogie
Change the objects to a hammer and a feather dropped on a tiny moon of say ten hammer masses. And make it a moon very low density and high surface area; say ten square miles of surface area so the hammer and feather could be dropped at the same time at a distance of 100 ft. apart.

This way, the hammer will pull the tiny moon more noticeably.

This should help make the answer more obvious; the hammer.

Oops. I just noticed that there were six pages of posts on this thread and I only read the first page. Probably my suggestion has already been made.
Works on the real moon with a real hammer and feather. Hammer hits first! - immeasurable in practice. The trick is to remember that all Galileo said was "they would both fall at the same speed" - which is true.
It's what the moon does that makes the difference!

80. Originally Posted by billco
Originally Posted by bogie
Change the objects to a hammer and a feather dropped on a tiny moon of say ten hammer masses. And make it a moon very low density and high surface area; say ten square miles of surface area so the hammer and feather could be dropped at the same time at a distance of 100 ft. apart.

This way, the hammer will pull the tiny moon more noticeably.

This should help make the answer more obvious; the hammer.

Oops. I just noticed that there were six pages of posts on this thread and I only read the first page. Probably my suggestion has already been made.
Works on the real moon with a real hammer and feather. Hammer hits first! - immeasurable in practice. The trick is to remember that all Galileo said was "they would both fall at the same speed" - which is true.
It's what the moon does that makes the difference!
I know and agree. My tiny moon would allow a measurable effect though, :-D

81. Originally Posted by bogie
Originally Posted by billco
Originally Posted by bogie
Change the objects to a hammer and a feather dropped on a tiny moon of say ten hammer masses. And make it a moon very low density and high surface area; say ten square miles of surface area so the hammer and feather could be dropped at the same time at a distance of 100 ft. apart.

This way, the hammer will pull the tiny moon more noticeably.

This should help make the answer more obvious; the hammer.

Oops. I just noticed that there were six pages of posts on this thread and I only read the first page. Probably my suggestion has already been made.
Works on the real moon with a real hammer and feather. Hammer hits first! - immeasurable in practice. The trick is to remember that all Galileo said was "they would both fall at the same speed" - which is true.
It's what the moon does that makes the difference!
I know and agree. My tiny moon would allow a measurable effect though, :-D
Yes but how many time, we should wait ?

82. Just to revive this little beauty one last time.......

Congrats Mr Cooper for getting the little story about this published in the latest issue of the UK Mensa magazine!! :wink:

83. Originally Posted by Its All Relative
Just to revive this little beauty one last time.......

Congrats Mr Cooper for getting the little story about this published in the latest issue of the UK Mensa magazine!! :wink:

Hey! I'd like to read that story! Can anyone provide a link to it? Or copy and paste the text (if that doesn't break any rules)?

Thanks,
william

84. whos idea was it to revive this thread?

85. Probably somebody who read what tsolkas was saying.

86. well who ever it is shouldnt read. its never good reading what maniacs say

87. Maybe zelos......

Maybe most scientits are just like you and would take such an insignificant tiny amount such as the time difference in this case and pass it off as being zero, as you obviously have done in your own mind.

Maybe thats why we have no quantum theory of gravity yet.

If its not zero, its something. End of.

88. Originally Posted by leohopkins
Maybe zelos......

Maybe most scientits are just like you and would take such an insignificant tiny amount such as the time difference in this case and pass it off as being zero, as you obviously have done in your own mind.

Maybe thats why we have no quantum theory of gravity yet.

If its not zero, its something. End of.
there is a differens between locking away a possible idea, excluding a crazy idea and listening to a mad man. the later one is just what tsolkas is. his idea goes against tons of data and facts. Einsteins didnt go against any observations in the realm they were done

89. who is this guy tsolskas ?

and if he is so sure about this, why doesnt he test them and present the reusults to the scientific community.

90. Originally Posted by leohopkins
who is this guy tsolskas ?

and if he is so sure about this, why doesnt he test them and present the reusults to the scientific community.
cause he know it will be falsefied

91. Originally Posted by william
Originally Posted by Its All Relative
Just to revive this little beauty one last time.......

Congrats Mr Cooper for getting the little story about this published in the latest issue of the UK Mensa magazine!! :wink:

Hey! I'd like to read that story! Can anyone provide a link to it? Or copy and paste the text (if that doesn't break any rules)?

Thanks,
william
Here is the text of the article, as submitted for publication:

"BILL COOPER with a Newtonian puzzler

I was recently trawling the internet for some information on the moon when I stumbled upon the subject of Lunar landings – fact or fiction? I decided a few days later to return to this subject and for sheer fun add my six-penneth to a forum. I chose a forum where the ‘owner’ clearly believed they had taken place (as I do) and to his great credit had provided knock-downs to all the ‘hoax’ evidence presented. I noticed, however, that he would occasionally ‘lose it’ and wondered whether I could convince him that something he would believe was ‘set in stone’ was in fact inaccurate.

The object I chose was the hammer and feather; would they really both hit the ground together? Newton’s mechanics predict only that they would both accelerate at the same rate. Newtonian mechanics does not say they will both strike the ground at the same time (using the Formula f=G(Mo x Mm)/r2) where Mo = mass of the object and Mm = mass of the moon. With A=f/Mo then acceleration due to gravity becomes A=(G x Mm)/r2.

Hence all objects independent of mass will ‘fall’ at the same rate of acceleration. Now that’s all very well but … the moon will also accelerate towards the object being dropped since the object being a mass has a gravitational pull upon the moon. From this the difference between the acceleration of the moon to the hammer, and the moon to the feather (if not dropped at the same time) becomes A = G (Mh-Mf)/r2. So if dropped separately, the time taken to strike the surface is different for each object. Now what happens when they are dropped together? As the two objects are released the moon will instantaneously begin to accelerate towards the gravitational ‘centre’ of the two objects and since the moon can only accelerate along a single axis at any one time, both objects it would seem, would strike the surface at the same time. Now consider this: If you drop two marbles onto an orange where one marble strikes the very highest point of the orange the second marble can only (if released at the same time from the same height) strike a point further around the circumference and therefore below, the highest point meaning it has further to fall. Therefore at this level of thinking the hammer would indeed reach the surface first.

My first ‘contribution’ to the forum was to say that: “The only evidence I had that the moon-landings were faked was that the hammer and feather should not have hit the surface at the same time”. Clearly, I thought, this would bring controversy. It did. Nobody who partook in the forum was able to ‘shoot down’ or disprove what I said. So would the hammer strike the moon surface first?"
======================End of Article ===============

I should like to make it very clear that the forum mentioned in the opening paragraph is not 'The Science Forum'.

Here's a link to the original, amusing and very tongue-in-cheek post...

Billco.

92. I'd also like to mention, sans what billco said, that there would definitely still be "air resistance" on the moon. Since the moon still has some small amounts of it, so even ignoring that the feather would still hit the ground last.

However I'm unsure as to how much resistance the feather would have on the moon. It may actually be so small that there's no difference. Or it may be slightly noticeable.

but that's all I can say, I think they'd hit the ground at the same time though.

93. Originally Posted by Jeremyhfht
I'd also like to mention, sans what billco said, that there would definitely still be "air resistance" on the moon. Since the moon still has some small amounts of it, so even ignoring that the feather would still hit the ground last.

However I'm unsure as to how much resistance the feather would have on the moon. It may actually be so small that there's no difference. Or it may be slightly noticeable.

but that's all I can say, I think they'd hit the ground at the same time though.
I have just read back through the whole thread and found no trace of billco indicating any form of atmosphere on the moon, although this is chucked in, it was by others.

94. no, what billco just posted which said the hammer would strike first. He did say nothing about atmosphere.

95. Since the maths used do not conatin any friction coefficients and, in the original post, words such as "uniform density" and "perfect sphere" occur it is likely a pure maths problem, that is, not in any sense a practical propostion (too many variables) just a 'thought exercise'.

96. Ah, I see. Nevermind then.

97. Bill - No. I didn't

98. h = 1.5 m, g_moon = 1.622 m/s^2, then the free-fall time interval should be t = sqrt(2h/g_moon) = 1.36 sec.
However, the hammer is in free fall for at most 1.1 seconds.
Is the moon gravity at that particular location stronger than usual or there is some other explanation?

99. Oi!

100. This must have been mentioned already but i just haven't the energy to go thru 7 pages to see. Did not this exact experiment take place on the moon by one of the astronauts of Apollo 12 or 15? I have seen a video of it as child. Oh, and just in case you haven't seen it, they both landed at the same time, wow what a surprise.

http://nssdc.gsfc.nasa.gov/planetary...ther_drop.html
Obviously, both hammer and feather landed at the same time.
The question is why they fell down FASTER (according to the video clip) than it should be observed on the moon.