Topic: Which hits first, the hammer or the feather?

[Markcb750]

Interesting, and true, but the errors involved due to the "complicating" factors far exceed the difference due to the combined mass CG/CM.


answer the questions, or quit obfuscating...Its your choice.  but do not selectively include one insignificant contribution to the elapse time while ignoring others.


A simple method of avoiding the issues is to state the problem more clearly.  (But then all this fun would not be had.)


to my way of thinking....

Mathematicians give us numbers but they don't know what the numbers are based on.

Physicists can explore the errors and look for old or new explanations.

Engineers give us real world solutions using the science the mathematicians and physicists taught us. 

Mechanics make engineer's dreams come true.

Mechanical Engineers are the best.   

[mlinder]

OK. something reminded me, I think, of the error galileo may have made. Or assumptions on his studies were flawed. Etc. Who knows.

In any case, the study I alluded to earlier may have involved something like this:

While the two objects dropped at the same time, being of equal dimensions and disparate mass, do in fact have a 'combined' gravitational field, since their proximity causes this, the fact that it is NOT in a vacuum creates the issues. The object of less mass is drawn to the object of greater mass, while both are traveling at, eventually, terminal velocity towards the largest mass in this equation, the earth. But terminal velocity is terminal velocity. It isn't measured in just one direction, so far as I know.
Since the object with the least mass must also travel towards the other object of greater mass, while traveling towards the object of greatest mass, the speed at which it is traveling towards the other object must be subtracted from it's speed towards the earth.
Does this work in a vacuum? I dunno, have to think about it for a sec, because terminal velocity is a function of resistance to gravitational forces.
But this idea causes other problems, problems of the idea of 'infinite', which caused a lot of issues in the airplane thread. SO lets preclude the ideas of 'infinite' for now.

[333]

I hate you.

[sangyo soichiro]

Interesting, and true, but the errors involved due to the "complicating" factors far exceed the difference due to the combined mass CG/CM.


answer the questions, or quit obfuscating...Its your choice.  but do not selectively include one insignificant contribution to the elapse time while ignoring others.


A simple method of avoiding the issues is to state the problem more clearly.  (But then all this fun would not be had.)


to my way of thinking....

Mathematicians give us numbers but they don't know what the numbers are based on.

Physicists can explore the errors and look for old or new explanations.

Engineers give us real world solutions using the science the mathematicians and physicists taught us. 

Mechanics make engineer's dreams come true.

Mechanical Engineers are the best.   

MarkCB750, you are still overcomplicating this simple little thought experiment.  I specified, "all else being equal" when doing the experiment on either the feather or the hammer.  Therefore, whatever "complicating factors" you are fretting about, apply to both the hammer and the feather. 

You're mathematically inclined, just solve for the collision time between two massive objects starting from rest without throwing out either mass.  I don't care how complicated or simple you choose to make it.  Just have two massive bodies collide and don't throw out either mass.  Let us know what you get.  Is that clear enough for you?

P.S. I'm surprised you haven't invoked Heisenberg's uncertainty principle.   

[sangyo soichiro]

But terminal velocity is terminal velocity. It isn't measured in just one direction, so far as I know.

That's true. 

Actually, all three objects move toward their common center of gravity.  For all intents and purposes (and to please the stubborn engineers  ), the earth moves so little in such an experiment, that it can be considered stationary. 

But it's a curious and interesting thing that, if you were driving from west to east, and you slammed on your brakes, by the conservation of momentum the earth spins up just a little tiny bit faster.  Of course, at any given moment there are people moving in every direction and slamming on their brakes so it all probably cancels out fairly nicely.  But nonetheless, conservation of momentum still holds.

[Markcb750]

Sorry soichiro they (the feather and the hammer on opposite sides of the moon) are not the same.

The relativistic effects can be significant around objects as massive as a mountain.  if one object is dropped next to a crater, and the other next to a mountain the timing of the event can be effected by the local gravity. You do understand that GPS takes relativistic effects into account to more accurately provide location.

You understand photonic pressure on a feather results in hundreds of time more acceleration then on a hammer (F=Ma).


As with the plane the answer you seek is obfuscated by the explanations you provide. 
Fun but not informative. 

[Joel]

But terminal velocity is terminal velocity. It isn't measured in just one direction, so far as I know.

That's true. 

Actually, all three objects move toward their common center of gravity.  For all intents and purposes (and to please the stubborn engineers  ), the earth moves so little in such an experiment, that it can be considered stationary. 

But it's a curious and interesting thing that, if you were driving from west to east, and you slammed on your brakes, by the conservation of momentum the earth spins up just a little tiny bit faster.  Of course, at any given moment there are people moving in every direction and slamming on their brakes so it all probably cancels out fairly nicely.  But nonetheless, conservation of momentum still holds.

Wouldn't that braking momentum be essentially cancelled out by the acceleration momentum required to reach speed in the first place?

[sangyo soichiro]

But terminal velocity is terminal velocity. It isn't measured in just one direction, so far as I know.

That's true. 

Actually, all three objects move toward their common center of gravity.  For all intents and purposes (and to please the stubborn engineers  ), the earth moves so little in such an experiment, that it can be considered stationary. 

But it's a curious and interesting thing that, if you were driving from west to east, and you slammed on your brakes, by the conservation of momentum the earth spins up just a little tiny bit faster.  Of course, at any given moment there are people moving in every direction and slamming on their brakes so it all probably cancels out fairly nicely.  But nonetheless, conservation of momentum still holds.

Wouldn't that braking momentum be essentially cancelled out by the acceleration momentum required to reach speed in the first place?

Yes!

[sangyo soichiro]

Sorry soichiro they (the feather and the hammer on opposite sides of the moon) are not the same.

Doggonnit!  I just knew if I were to introduce something else for illustration purposes, someone would get confused by it!  If it's confusing, then forget it.  It's not important.  Stick to the original question.

The relativistic effects can be significant around objects as massive as a mountain.  if one object is dropped next to a crater, and the other next to a mountain the timing of the event can be effected by the local gravity. You do understand that GPS takes relativistic effects into account to more accurately provide location.

You understand photonic pressure on a feather results in hundreds of time more acceleration then on a hammer (F=Ma).


As with the plane the answer you seek is obfuscated by the explanations you provide. 
Fun but not informative. 

Why is doing the experiment on each object, individually, with all else being equal, so hard to understand?  Now I have to explain away craters and mountains and radiation pressure I never introduced to begin with.   

Okay, radiation pressure, assume equal surface areas (or just assume all else being equal!).  Jeez, do I really have to specify everything? 


MarkCB, just solve for the collision time between two massive objects starting from rest without throwing out either mass.  I don't care how complicated or simple you choose to make it.  Just have two massive bodies collide and don't throw out either mass.  You may have as many craters and mountains as you like so long as you drop both masses at the same spot (or are you going to still be confused about the example of each being on opposite sides of the moon?).

[seaweb11]

I'm going with the "if anything can go wrong it will" principle.

At least it did for me today

How about if a guy took a dump in zero gravity and peed at the same time?  would he get wet or dirty?

OK back to the absurd.

[Markcb750]

Sorry soichiro they (the feather and the hammer on opposite sides of the moon) are not the same.

Doggonnit!  I just knew if I were to introduce something else for illustration purposes, someone would get confused by it!  If it's confusing, then forget it.  It's not important.  Stick to the original question.

The relativistic effects can be significant around objects as massive as a mountain.  if one object is dropped next to a crater, and the other next to a mountain the timing of the event can be effected by the local gravity. You do understand that GPS takes relativistic effects into account to more accurately provide location.

You understand photonic pressure on a feather results in hundreds of time more acceleration then on a hammer (F=Ma).


As with the plane the answer you seek is obfuscated by the explanations you provide. 
Fun but not informative. 

Why is doing the experiment on each object, individually, with all else being equal, so hard to understand?  Now I have to explain away craters and mountains and radiation pressure I never introduced to begin with.   

Okay, radiation pressure, assume equal surface areas (or just assume all else being equal!).  Jeez, do I really have to specify everything? 


MarkCB, just solve for the collision time between two massive objects starting from rest without throwing out either mass.  I don't care how complicated or simple you choose to make it.  Just have two massive bodies collide and don't throw out either mass.  You may have as many craters and mountains as you like so long as you drop both masses at the same spot (or are you going to still be confused about the example of each being on opposite sides of the moon?).

If you wanted to know what happens when two objects are allowed to fall toward each other, without regard to any other objects in the universe, why ask about a feather and a hammer on the moon?

This is not a question implied by the question you asked.

In your greatly simplified case, the pair of objects with the higher mass will fall toward each other faster then the lower mass pair of objects.

[Markcb750]

I'm going with the "if anything can go wrong it will" principle.

At least it did for me today

How about if a guy took a dump in zero gravity and peed at the same time?  would he get wet or dirty?

OK back to the absurd.

I don't know about you but my pee comes out with significant velocity, my dumps very close to zero speed.  Unless I have the "wild axe handles" then my dumps have significant speed...

[333]

I'm going with the "if anything can go wrong it will" principle.

At least it did for me today

How about if a guy took a dump in zero gravity and peed at the same time?  would he get wet or dirty?

OK back to the absurd.

Given the principle you quote, both.

[mlinder]

Ove had three gin and tonics, one PB tallboy, and six 1554's (http://www.newbelgium.com/beer/1554 , very good beer) today, and I just finished cooking dinner for myself and a roommate. I'm going to watch some porn and go to sleep.
Howeer, tomorrow, I will ask for specifics concerning this question. There are only three questions that need to be asked, assuming EVERYTHING in the universe is the same at the time of the drop of both objects.

[mlinder]

Okay, so here are my questions, assuming all else in the universe is in a state of stasis for the purposes of dropping the feather and the hammer.

1.} Are we indeed in a perfect vacuum?
2.} Do the feather or hammer exist while the other is being dropped, and if so:
3.} Where are they when the other is being dropped?

[Inigo Montoya]

Sorry but vacuum or not, the object with greater mass will be pulled stronger than the object with less mass. A vacuum only affects the resistance. A vacuum is a lack of atmosphere and nothing more. It will not affect mass or gravity in anyway. It only affects the resistance generated by an object moving through it. The less vacuum, the more resistance.
So maybe I am wrong but I just doubt the feather is going to drop like a rock solely because of a vacuum. But then I do not know if this has ever been able to be proven 100% Without someway to prove it, the math could be wrong.

[mlinder]

Sorry but vacuum or not, the object with greater mass will be pulled stronger than the object with less mass. A vacuum only affects the resistance. A vacuum is a lack of atmosphere and nothing more. It will not affect mass or gravity in anyway. It only affects the resistance generated by an object moving through it. The less vacuum, the more resistance.
So maybe I am wrong but I just doubt the feather is going to drop like a rock solely because of a vacuum. But then I do not know if this has ever been able to be proven 100% Without someway to prove it, the math could be wrong.

It could affect the issue, depending on whether, and where, the hammer exists while the feather is dropping, depending on the mass of both the hammer and feather. Math really can't be wrong unless the problem is wrong, meaning, the correct question has to be asked to receive the correct answer. The math will always asnswer the question you ask it.

[Inigo Montoya]

but the amount of gravity is based on the mass of the object. A hammer is not that big and unless the feather was virtually touching it, I doubt that is even a touch of an issue, even in a vacuum.

[mlinder]

We haven't determined the mass of either object, but yeah, assuming they are 'normal', you are right.

[333]

Vin (I'll play along) where did that avatar come from?  And what the heck is it supposed to be?

But more importantly, what will be next from mlinder?

[Inigo Montoya]

It was one I found. i dont remember where exactly though. I know I did a lot of looking to find one that would "fit".
It is kinda matrix/dragonballZ-ish.
So I guess you could play along with that.

[burmashave]

You are all missing the random effect brought upon by dropping them separately. I was unaware of the random component of Galileo's experiment until I saw it in action at the Boston Museum of Science. The random effect prevents both from ever hitting at exactly the same time as shown by the interactive demonstration at the museum.

[mlinder]

Some physicists would say it's not random at all, it's merely an undefined parameter in the equation, making the equation imperfect, not the actual physics.

[mystic_1]

mystic_1

[tramp]

although there is no atmosphere there is gravity
gravity would affect the hammer more because of weight and mass