Do heavier objects "fall" faster?
 

Okay, it is common knowledge that if you take out aerodynamic properties, Earth's gravity will exert acceleration forces of 9.8 meters per second squared (32ft/s or 22mph).

That is because Earth's gravity pulls on all objects the same regardless of the object's mass.

And since all objects do have mass (exerting gravity), wouldn't the object that is falling also "pull" on the Earth? Thus a heavier object, with more mass, and gravity will pull on Earth more than a lighter object would.

Which in turn, if you drop two objects, one light and one heavy, the heavy one would exert more gravitational force on earth, thus "fall" faster than the light object.

Mathematicians? Physicist?

^ Consistent w/ gravitational laws.

No, I am not kidding. :roll:

Thank you for bring that up. . .

According to Newton's 3rd Law, the Earth itself experiences an equal and opposite force to that acting on the falling object, meaning that the Earth also accelerates towards the object.

No, a heavier object will not fall faster.

Again, I just pointed out Newton's 3rd Law.

Or since you "always understood this stuff", please explain Newton's 3rd Law and how it does not apply.

I remember last year this was explained in my physics class but ive forgotten the equations already :?

the heavier object exerts an equal pull on the earth as the earth does on it, which the earth will pull the heavier object more then the lighter object.

they will both fall at the same speed

^ I know about the experiment in the vacuum tube as well, but I ask again, does this mean that Newton's 3rd Law is wrong?

Correct, which is why the heavier object since it has more "pull" not fall faster?

By the way BMW06 no "offence" taken. Just trying to see if you could explain it to me, or maybe you should read that Wikipedia link you posted. Since "a 7 year old could understand it."

man, your missing the point.

this is a simple pendulum test here

AE86, tie some string with some fishing weights at the end, then do the same, except a string that is longer; then the same with two more strings to = the lenghts of the other two, but each with more mass. observe ;) pendulums can actually be used to measure gravity :)

The force is gravity.

Only thing I know is that when I jump in the air, I usually return safely to planet earth

http://www.school-for-champions.com/...ons_cradle.htm

By the way, this is The Law of Conservation of Momentum, not gravity.

Unless you got those new Nike Air Jordans, those make you jump really high ;) .

Well I usually wear these

http://www.transportstation.org/pict...-Shoes-Med.jpg

Interesting question.

I assume it would depend on the circumstances.

At some point unless the differences in the two items being dropped were very great. The simple act of measuring the result would change the answer. This has some thing to do with someones cat, I have forgotten the name of the owner, I think it started with an S like Schroder or Schrodenger's Cat.

well as you have an object that is a bit lighter than the other one i imagine it might fall faster towards the earth but probably about this much faster 0.000000000000000000000000000000000000000001 s

so it can't really be seen directly or properly measured (physics is an incredibly accurate science but come on this is quite impossible imo)

if you enlarged the scale, of course the gravity constant will be changed (you want to let it fall higher but you are getting further away from the mass (earth) and so you get 'lighter') so overall it probably can't be proven.

you probably mean Schreodingers cat. dunno quite exactly what that's about tho :P

wow there are some interesting theories on this page...

not to try and sound like a smart ass but the guy asks a legitimate question and i see a lot of half assed responses...

gravity is a force working between objects with mass. any object with mass will excert a gravitational pull. gravity has an infinite reach which means that the mass of a needle will have a gravitational pull on the farthest of stars. Needless to say, this force is very weak. this is because gravity is a very weak force, consider the mass of the earth and then the relatively modest force it's gravitational pull excerts on us.

it is therefore true that because a heavier object has a greater mass the gravitational pull or force between it, and the earth will be greater. BUT since this force is so weak the difference in drop speed is practically imeasurable.

hope this helps

Both of you are correct. Fact of the matter is that any object will exert gravational pull on earth, and the more massive object of course will exert more pull.

But the problem is measuring it. It is hard to measure when one object is so much larger than the other. A sphere (steel ball or snow ball) to earth.

It all has to do with relativity.

Fact of the matter is that this was already Proven by Newton's 3rd Law.

Thank you guys.

Exactly. Thank you Malte ;) .

your perfectly welcome... knew this degree in enginering was good for something :wink:

You might "understand" science. But you clearly can not read or comprehend the source you posted yourself.

And by the way, common sense is not very common, thank you for proving my point.

Yes, heavier objects to fall faster, air resistance is the key. Butit's only noticeable over long drops.

http://www.physlink.com/Education/AskExperts/ae6.cfm

Yeah thanks, thats the guy, Schreodingers Cat. I'll look it up tonight.

I stated if you do not include aerodynamic properties (drag) ;) .

Force = mass x acceleration and therefore acceleration = force/mass. However, the force applied on a falling object is directly related to its mass (9.81 Newtons of force per kilogram.) Because of this direct relationship, all things fall at the same rate when there is no friction. All things in free fall accelerate at 9.81 meters/second squared

However, in reality, there is friction to worry about. So if the amount of surface area is large relative to the amount of mass, a significant amount of drag will result. For instance, a feather will fall very slowly. If you were to crush and compact this feather into a ball, the surface area and resisting drag would be greatly reduced. The feather would then fall much faster. see, simple

at 79TA: im not gonna say you are wrong when stating that all things fall at the same rate(due to the number of significant digits that you seem to involve), but i will say that your explanation is oversimplifying the problem.

You speak of a force, but what you need to include in your conciderations is the fact that the gravitational pull between two objects consists of a contribution from either object.

the force between two objects is given from newtons law of gravitation:

F=(G*M*m)/r^2

where G is the gravitational constant, r is the distance of separation and the masses are denoted M and m respectfully.

this correlation shows that even though the mass of the smaller object (m) is insignificant in relative comparison to the larger object, the fact remains in theory the size of the force increases when either of the masses do...

Your arguements aren't all that clear guys. You aren't clearly denoting the objects acceleration.

In absolute terms:
F= mass x acceleration. The force of gravity is directly related to the mass of the object (duh). Your simultaneously changing both the F orce of gravity and the mass on the other side in the same proportion. Thus the masses cancel out leaving acceleration to be unaffected by the individual masses. It is a simple algebra problem. The two items will accelerate and travel at the same speed no matter what the mass. F=G(Mem1/r^2)=m1*a m1 cancels out to G(ME/r^2)=a Where Mass of the earth (Me) Mass of the object m1. r= distance from earth. a= acceleration of object. G= gravitational constant
Thus the rate of acceleration of the object dropped only depends on the distance from the earth!


But... And I say but..
If you take the same objects acceleration relative to the earth you have to account for the movement of the earth itself due to the object.
The earth is accelerating towards the item that is dropped. And the bigger the object the greater the force on the earth.
Again the equation is F=G(Mem1/r^2)= Me*a.... This time Me cancels
Giving you G(m1/r^2)=a on the earth.... Meaning the acceleration of the earth is proportional to the weight of the object.

Thus the answer becomes, what frame of reference are you watching the object from. If you are watching from earth there would be an acceleration difference. If you are watching from a frame of reference from somewhere off planet the objects will accelerate with the same rate.

^ Thank you for clearing that up.

Not taking into account drag, I would have thought, like Graywolf, that acceleration would be the same, thus the two items would fall at the same rate.

However, in the real world, there is drag, and items will obviously fall at different speeds, and the more aerodynamically efficient ones will fall quicker. Still, weight will not be relevant. Right?

I really should stick to history and philosophy. This science stuff is too complicated.

Let me say first that I have very little background in fluids. In terms of modeling it with physics, your starting to get over my head when you get into drag.

That being said I am sure the mass of the object falling is important, but other aspects are as well. With aerodynamic drag there are so many factors you probably could not get the same result with 2 runs of the same object. Some of these include the surface area of the object, shape of the object, and speed of the object.
Then you have density of the air, temperature of the air, pressure, direction of air flow, etc (which are all interrelated.)

The air provides a force to the object pushing up.. the object pushes down on the air. Remember from the equations above the force of the falling object is f=m1a where a is a constant 9.8 m/s^s.
So now we pick a heavier m1. The force of the heavier object falling is now higher since we just showed its non earth relative acceleration is constant. This means if it hits the air and encounters the same friction force (aka all else equal), the net force pushing downwards afterwards will be higher then that of a lighter object. A great F with the same mass means a greater acceleration. Thus a heavier object all else being equal will have a higher resistance (momentum) to the slowing effect of the airodynamic drag.


Info on calculated drag and the like.
http://hypertextbook.com/physics/matter/drag/

On a side note, ae86_16v have you seen the film of the astronauts on the Moon dropping the feather and the hammer to prove Galileo’s theory on gravity correct? Its very cool to see what happens without air resistance.

Ahh, and of course its on youtube:

Yeah definitely ;) . I also saw the one in a vacuum tube too, that was cool.

When I take a shit, the bigger poop causes a larger splash onto my buttocks, but I think that doesn't have to do with the speed at which it fell into the toilet so much as the mass of my poop, and the water it displaced. So, I don't think this example is very helpful. Sorry. :?

You guys are debating newtonian physics. It is nothing but a generalization. Gravity doesn't even exist.

^^ how do your balls hand downwards then ;) ...

:lol:

... Sounds about right to me (says the physicist).

As far as Schroedinger's cat is concerned...

The infamous Schroedinger's cat problem is a thought experiment that has applications to quantum mechanics and various other high-level strains of physics.

Basically it is this:
We place a living cat into a steel chamber, along with a device containing a vial of hydrocyanic acid. There is, in the chamber, a very small amount of a radioactive substance. If even a single atom of the substance decays during the test period, a relay mechanism will trip a hammer, which will, in turn, break the vial and kill the cat. The observer cannot know whether or not an atom of the substance has decayed, and consequently, cannot know whether the vial has been broken, the hydrocyanic acid released, and the cat killed. Since we cannot know, the cat is both dead and alive according to quantum law, in a superposition of states. It is only when we break open the box and learn the condition of the cat that the superposition is lost, and the cat becomes one or the other (dead or alive). This situation is sometimes called quantum indeterminacy or the observer's paradox: the observation or measurement itself affects an outcome, so that it can never be known what the outcome would have been if it were not observed.

oh and btw the person who first finds gravity waves or the medium that the gravitational force is transportet in, wil lget the Nobel prize of physics.

that's what my physics professor said yesterday ;)

Results 1 - 10 of about 1.480.000 for gravity waves (0,10 seconds)

*sigh* Have you ever tried Google? ;)

please do some research before you try owning somebody :roll:

here's the full article on it: http://en.wikipedia.org/wiki/Gravitational_wave

They fall the same speed.

Want to make a test? Just get a book and a sheet of paper, make the book bigger in area than the paper. Then just put the paper on top of the book (on the cover) and let it loose. They will fall together, same speed, same time.

That has more to do with the aerodynamic properties of the book and the fact that the turbulence that forms on top of the book would force the paper to lie flat against the surface of the book.

Do heavier objects "fall" faster?

well ... as i see it .. not being a dork and all ...

heavier objects acclerate to terminal velocity faster then lighter objects .... ;)

that is if you take out wind speed drag coefficients and shit .... like you read in the science books back in school " In Perfect Condition " .. ;)

Thanks for explaining the cat. Your explaination was better that what I read on line.

Nope...terminal velocity is deteremined by the fact that there IS wind resistance (or drag if you like). In the most sterile of conditions, i.e. a vacuum, a 25lb weight and a feather would fall at rates indistinguishable from each other. Now...the argument leveled earlier on in this thread that suggests that if you have two very massive objects exerting gravitational pull on each other, that the rate at which the two closed distance would be substantially greater than an instance in which you had something like a feather and one very massive object is accurate. But with the Earth being as massive as it is (by massive I mean "heavy, exerting gravitational pull"), and everything else that we test being so light, it is unlikely that we would ever be able to see a great deal of difference in the way that anything falls towards the Earth. Thus, following the equations F=GMem/r^2 = m*a and F=GMem/r^2 = Me*a, as posed in Graywolf's post, we arrive at the conclusion (more or less supported empirically) that all objects falling towards Earth experience the same gravitational pull.

In theory and for the sake of philosophical argument, yes.

But how many times has the box been opened and the cat found alive?

Most intelligent post in this thread.

:thumbsup: for looking at the whole picture.

yep all the objects experiece the same gravitational put which varies with altitude and blah blah ...... the thing is ... if the weight of one object is 2 and the weight of the other object is 4 .. what then ? .... the gravitational force is not the same on everyobject .. it varies with the weight of the object ;) ... why is a 20 kg weight heavier then a 2 kg weight ? when you try lifting it up :) ... because more gravitational pull is being applied to it
which mean the gravitational pull multiplies according to the weight ;) ..

i donno what i just said :? 8)