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I was sent by M21 Sniper to seek the expertise of a one Mr. Mudd and any other pilot extraordinaires.

We were having a convo on world affairs board about some physics stuffs.

The original thread in all its glory is:
http://www.worldaffairsboard.com/showth ... ge=3&pp=20

Basic premise:
Mr. Newton once said to me if you have two planes of different masses, having the same acceleration and initial velocity, they'll have the same turning radius.

Also, It makes no sense to me why is it that a f-16 can outmanuever an f-15 IF both were experiencing the EXACT SAME acceleration and both having the SAME initial velocities (basically what i said above). Or for that matter a shoe outmanuever a vodka bottle in that situation. I mean it's basic all basic kinematics. You tell me the the acceleration and initional conditions (if you really want to make me mad, tell me its angular accelerations too, its intial angular velocities and intial Euler angles), I'll tell you where your vodka bottle is.

But M21 isn't convinced and is taking the opposite position. I guess he doesn't think too kindly of us lowly physics guys and wants you guys to settle it.

So is there some secret physics you guys are hiding or what?


The convo went a little something like this (I edited it a lil, to shorten it):


{Begin never ending post}
<b>berkut:</b>
Centripetal acceleration has nothing to do with the size or the mass of the object. THe only factors are radius of the turn and speed. Simple physics. So you are wrong on that one.

If two planes, one tiny and one huge are going the same speed, and experiencing the same g force, then they are turning within the SAME radius. a = v^2 / r


<b>M21 Sniper:</b>
Wrong. Mass of the object in motion creates outward kinetic energy as the object attempts to change direction.

What you are saying is only true in zero G, where objects have no mass.

If you want to ask some real fighter pilots go here...

www.a-10.org (discussion forums)

Post your question in the general aviation section and address it to Mr. Mudd. He is a former F-16 pilot and USAF weapons school instructor.

He'll tell you all you want to know.


<b>berkut:</b>
Newton's 2nd law of motion. G-force is only a measure of acceleration

Wrong! Objects have mass even in the absense of gravity (!!!!!!) (you are talking about weight, which has nothing to do with physics). If you pull a tight loop in some X-fighter in space you will still experience a hell of G force.

To make this short: You are right but for a different reason which involves the design of planes which as a consequence directly relates their size to performance, not their G rating. I am just being a smart ass as an engineer.


<b>M21 Sniper:</b>
Regardless of the X, Y, Z behind it, a heavier fighter will have a larger turning radius at an identical G load than a lighter one because it will have more momentum pushing it outward.


<b>feynman:</b>
Well...if what you mean by this is that two planes of different masses having the same velocity and acceleration will have different turning radius...then that is incorrect. As berkut has already said.

Will the heavier one have more momentum? Certaintly! (assuming of course they have equal velocities). But all this means, is that a larger force will have to be applied to the more massive fighter to obtain the same acceleration.

What "more momentum pushing it outward" is supposed to mean....i'm not sure. Momentum doesn't "push". The only thing that can change the state of motion of an object is a force. If what you meant was that there is a "centrifugal force" pushing it out...well "centrifugal force"....isn't really a force. It is a by-product of being in a non-inertial (accelerating) reference frame.

The point remains the same: two objects, differeint in mass, having the same velocity and acceleration will have the same turning radius.


<b>[[Originally Posted by M21Sniper
OK then Feynman, please do explain why an F-16C, with an identical 9G turn rate as the F-15C has, at a nearly identical optimum corner speed, can turn circles around an F-15C.(That is a fact beyond dispute)]]</b>

<b>feynman:</b> So, if it's because of mass, I guess the F-16 and the F-15 are gonna be turning circles around the F-22 when they are all doin 9gs/same velocity? Since F-22 is the heaviest, right?

I don't care if its a f-16c vs f-15c or a feather vs f-16c. IF they are experiencing the same acceleration, and have the same initial velocity, they will move in EXACTLY the same way (their COM will). That is a fact beyond dispute. Please refer me to any USAF pilot that knows about these planes and physics that says different. He should be getting the nobel prize in physics. So my previous reply stands as is.

Now, like I said before, I am not a military/aeronautics expert by any means so the only way I can see my previous reply reaching the wrong conclusion is if my assumptions were wrong. So maybe go over those and make sure I was interpreting what you were saying correctly. The beauty of physics is that I can prove what I said without knowing the details of why it's happening. A reson physics is so powerful because of its abstractness. You tell me the acceleration (as a function of time, or poisition), the initial velocity (v(t=0)), and the initial position of something(r(t=0)), I can tell you where it will be in the future. Notice that mass is nowhere in my requirements of what I need to know about. I can show you the math behind it if you want, but it would be pointless unless you've taken differential equations.

Lets look at a simple and more intuitive example. Lets say I have a f-16 and a bowling ball and I drop (meaning 0 initial velocity) them in a vacuum on earth. They will both have will the same acceleration, right? And If I drop them from the same height they will reach the ground at the same time, right? This is regardless that they have different masses. This is the nature of knowing the acceleration of an object, its initial velocity and position, you know exactly what's gonna happen.

But I believe you that the f16 can out manuever the f15 so lets try to find out why. I believe we will find out that all things were not equal, like we are assuming (regrading initial velocity and acceleration). So, again, I don't know anything about f15 or f16 really but I'll try to make some guesses of what might be happening and maybe you can fill me in on some details. I guess my first question is about the f15 and 16 pulling these 9gs. Is that just a semi-instantaneous thing that just happens for a little while or what? Can the f16 sustain higher g's for a longer period of time than the f15? If so our problem is solved.

<b>[[Quote:
Originally Posted by M21Sniper
When a fighter attempts to change direction(or a car), it's mass wants to keep going in the same direction it was going. The more mass, the higher the impetus to resist a change of direction.]]</b>

<b>feynman:</b> Yup. Like I already said, if you want the more massive fighter/car to change direction like the less massive one, you must apply MORE force to obtain the SAME acceleration. So a larger force is being applied to the f16, relative to the f15 to, obtain his acceleration of 9gs.

{end eternity}



Edited by - feynman on Aug 13 2004 9:17 PM

Edited by - feynman on Aug 13 2004 9:21 PM

Edited by - feynman on Aug 13 2004 9:23 PM

OK Mudd, dazzle us.

T7, Thunderstruck, Coach, or any other pilot feel free to chime in with opinions.

"Freedom is never more than one generation away from extinction"

Ronald Reagan

Just for clarity, here is my position:

A more massive aircraft will have a larger turning radius than a lighter aircraft if all other conditions are equal. It is my understanding(as a guy with basic math skills, lol) that the outward momentum of the heavier fighter will require more force to overcome as the fighter turns, increasing it's overall turn radius(Not AoA, turn radius).

Am i wrong?

"Freedom is never more than one generation away from extinction"

Ronald Reagan

It sounds right. I'm not a pilot, but it seems right. Are you guys also taking aerodynamics into consideration? Drag and such would factor in here.

"Some pup"
Nickname by Fenderstrat72

_________________
Evil is evil, no matter how small.

<BLOCKQUOTE id=quote><font size=1 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>
It sounds right. I'm not a pilot, but it seems right. Are you guys also taking aerodynamics into consideration? Drag and such would factor in here.
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>

Irrelevant. Forces are what produce accelerations, sure. But what's relevant is that they both have the SAME acceleration at all times. I don't care what combination of forces does it though.



Edited by - feynman on Aug 14 2004 11:36 AM

Sure I will bite....

I need to start charging lecture fees....

I'll be typing up a little synopsis. Standby..to standby..

"The power to Destroy the planet, is insignifigant to the power of the Air Force----Mudd Vader

Ive read both your arguments and I am seeing many flaws to them. This is more to the point that you guys are not fully informed on all the relevent subject data that will explain the clear cause and Effect. Applied Sciences in one dicipline is not enough to explain the full dynamic of the Aircraft handling characteristics and Basic Flight Manuevering.

I think I will write a response that is more in line of being educational rather than argumentative. This I think will bring more substance to your discussions.

Will see how much carpet time this buys me, been a while since ive pissed the food chain off, and i'm feeling sporty today...

Here we go...

Sustained level turns:
F15 @37,000lbs Sea Level (standard day temp)
Quickest Turn
21 Degree a Second @ .72 mach (9 g is Structural limit
Radius Turn in Feet= 96.8 x KTAS divided by rate of turn.

Tightest Turn:
15 Degree a second @ .24 mach 2.5 g's load factor

F16 @ 22,00lbs Sea Level (standard day temp)
Quickest Turn:
24.1 Degree a Second @ .53 Mach 7.8 g's load Factor
Radius Turn in Feet= 96.8 x KTAS divided by rate of turn.

Tightest Turn:
14 Degree a Second @ .24 Mach 2.3 g's load Factor
1217 feet.

As you can See Different Weight Aircraft with a similar Drag Index of a Dogfight load (Gun and 2 aim 9's)

Each has a Different Envelope to get the Desired Flat turn performance The choice is Fastest turn in the circle or the Tightest Circle.

A fighter pilot needs to understand the variables of performance for their adversary and then apply their aircrafts best traits to offset a desired outcome that separates a smoking hole in the ground from an ace.


There are more variables we need to look at when flying at lesser density atmosphere levels

The Medium to High altitude Fight: 30,000 feet

F15C @37000lbs
Quickest Turn:
8 degree a second @ .9 mach 8.5 g's load factor
Tightest Turn:
7.5 degree a second @ 7.3 mach 3 g's load factor

F16c @22,000lbs
Quickest Turn:
14.1 degree a second @ .97 mach 7.5 g's load factor

Tight turn:
9.5 degree a second @ .65 mach 3.4 g's load factor

The decisive factor between the F15C and the F16C is the Fact that the F15C can Apply more G's with weight because of the Much larger Wing Area and Thrust. The F15C is applying more AOA units while the F16 In CAT 1 FLCS limitation has to apply Less AOA to get the desired Effect.

If we were to Go past the 28,000lb Cat1 Limit and Fly Cat 2 The F16 would be unable to fly at these extremes because the flcs Computer is preventing structural failure due to asymmetrical weigh distribution. Loads.

There will be more variables to look at now for Combat performance.

Rate of acceleration transients from Mil Power to AB. at given density, Mach and Altitude

Rate of Climb At a Given Mil, AB and Units of AOA applied to a Climb Schedule in degrees.

The most important to evaluate is in the aircrafts Departure Characteristics. Or as i like to refer to it as the "Region of reduced stability"

I will Post some more thoughts tonight. Wife has a list of honey do's and im running out of manuever envelope. This will give you guys something to chew on.

Retrogradeing south


"The power to Destroy the planet, is insignifigant to the power of the Air Force----Mudd Vader

Edited by - mrmudd on Aug 14 2004 3:14 PM

Mudd, You should really think of throwing your weight around as a prof of aerospace engineering in a University; the grabasstic kids would get a kick out of you.<img src=icon_smile_wink.gif border=0 align=middle>



Edited by - tritonal on Aug 14 2004 2:40 PM

Nice details I look forward to your educational response on the subject.

However, I think you guys are reading more into my claim then there is. My claim is simple, pure kinematics, and doesn't depend on the details of any craft/aerodynamics/race/creed/color. It's a very basic claim that anyone would encounter in any beginning physics class. I will write a reply on the details of why it is true.

Get ready for some horrid ASCII math notation!!

Snipe is Incorrect with the premise of the F15 and the F16 shareing the same values. The data I posted above shows their optimum baseline Performance. These performance figures are not True physics theory. this is based off of Performance data of The aircraft in Reference to its stated Lift Vectors and Thrust. ( It is these forces that are required to counteract Centripedal force)

The F16 being Lighter and having different wing area/Lift Vectors Does not need to apply the same rate of Load Factor (G's) Or velocity as the F15 is required For compared rate of Turn in degrees per second. I think Snipe is understanding this but did not know the applied sciences behind it clearly.

Being that the F15 is capped at 9g due to a structural limit. It can exceed this . The F16 FLCS atempts to limit at 8 g's I will do comparisons at 7g's at Sea level standard day atmosphere.

The Following performance Tables are not based on Flat rate physics but of Thrust and Lift vectors applied to counteract the Force of G acceleration

F15 @ 37,000 lbs
7g = .6 mach 18.5 degrees per second

F16 @ 22,000 lbs
7g = .43 mach 23 degrees per second

F16 @ 28,000 lbs
7g = .58 mach 21 degrees per second

To allow the aircraft to better perform its flat physics property. The forces of AOA units/matched thrust vectors, Thrust Vectoing, Wing lift Planforms Will all change these variables as they attempt to Fight the nominal Centripedal Force value specified by velocity and G acceleration.


"The power to Destroy the planet, is insignifigant to the power of the Air Force----Mudd Vader

Edited by - mrmudd on Aug 14 2004 4:29 PM

Ok. Now to get into some horrible math notation as promised.

--------------------------------------------------------------------------------------------------------
Let's define some notation and definitions:

X(t) represents a position vector.
I will denote the position vector of an object p, which is a function of time, as X_p(t).
(So X_p(t) = (x_p(t), y_p(t), z_p(t)) in cartesian coordinates)


f'(t), f''(t), ... represents the first derivative of a function f with respect to t, the second derivative of f wrt t, etc

S[a,b]f(t)dt represents the definite integral of the function f(t) wrt to t,with lower limit t=a, upper limit t=b
(S was the closest thing I saw on the keyboard that looked kind of like the integral sign)

What i mean by two things having the same motion is: their velocity graphs are the same and their position graphs vary at most by a uniform translation. You could probably come up with a more general def. for motion, but this works for here. (for instance maybe make it rotationally invariant also)
----------------------------------------------------------------------------------------------------------

Once again. My claims:

<BLOCKQUOTE id=quote><font size=1 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>
Proposition 1: Given two objects, possibly of different mass, denote their masses as m1 and m2 respectively. Assuming both object's center of mass experience the same accelration, denoted by the function a(t), and have the same initial velocity, X'(0), then each's center of mass ,X_p1(t) & X_p2(t), will follow the exact same motion.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>

(Note, I could have claimed some thing about object orientation, etc but I tried to keep things as simple as possible. The conclusion would be the same anways. I actually already made it more general than is needed, can you can spot it?)

<BLOCKQUOTE id=quote><font size=1 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>Corollary 1: If two objects have the properties given in claim 1, then they will have the same turning radius. <hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>
This immediately follows Prop. 1 since both follow the same motion, then, regardless of mass, their turning radius will be the same.

(Notice there is no talk of forces in here. We can disregard all the aerodynamics, mass, smell, color, whatever. WHAT GOOD ARE FORCES??? Forces and mass tell us the acceleartion of a mass...but we already know all we need to know about acceleration...they are the SAME! So the forces and masses involved are of no consequence to the claim. Please make sure this is clear to you before you continue. It is of fundamental importance)



Alright. <b>So, to be clear, the proposition and it's corollary are all I claim.</b> Here are the details of why Prop. 1 is TRUE.


For every time t>=0 there will be some unique acceleration given by some vector function a:R->R^3

Acceleration is by deffinition: X''(t)

So we have the 2nd order differential equation X''(t) = a(t), for each object

X_p1''(t) = a(t)
X_p2''(t) = a(t)

In physics, if we want to describe the motion of a a mass, we want to know X(t) for times, t>=0.
From X(t), although interesting on its own right, we can find the other interesting stuff...velocity, acceleration, jerk, kinetic energy, whatever. Of course, some of these things we might have known before hand, but you get the picture.

So Lets solve the equations.

Integrating once we get the velocity funtions:

X_p1'(t) = X'(0)+S[0,t]a(t*)dt*
X_p2'(t) = X'(0)+S[0,t]a(t*)dt*

integrating one last time we get we get the position functions:

X_p1(t) = X_p1(0)+X'(0)t+S[0,t](S[0,t*]a(t**)dt**)dt* (t* and t** are just dummy variables, of course)
X_p2(t) = X_p2(0)+X'(0)t+S[0,t](S[0,t*]a(t**)dt**)dt*

(note, dont worry about the scary looking S[0,t](S[0,t*]a(t**)dt**)dt*, its just some function of time that X_p2 and X_p1 have in common)

So we see, given the initial conditions, there is a unique solution. To formally establish the uniqueness and existence of solutions to classes of ordinary differetial equations, such as these, see Picards's existence theorem.
http://mathworld.wolfram.com/PicardsExistenceTheorem.html

So is the motion of the two the same? YUP. Inspect above...we see:
X_p1'(t) = X_p2'(t), the velocity graphs are the same.
X_p2(t) = (X_p2(0)-X_P1(0))+X_p1(t), welp...X_p2(0)-X_p1(0) is a constant, it's just the two object's COM initial displacement from each other. So Yes, Their position graphs only differ by a uniform translation.

So, it's been shown they have the same motion, based on the assumptions I stated. Hence they will also have the same turning radius regardless of mass.

QED

It could be made more rigerous...but there isn't much point. I assume there are no anal mathematician's here that want me to tell you why I can take the integral of certain functions and such, right? If there are any questions about any of how/why I defined some things in here, feel free to ask I, again, appologize for the horrible ASCII math.

Just curious, Mr Mudd, where are the flaws in this argument? Even if there were minor ones, you agree with the proposition and collorary's statements, right?


Edited by - feynman on Aug 14 2004 6:45 PM

<BLOCKQUOTE id=quote><font size=1 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>Just curious, Mr Mudd, where are the flaws in this argument? Even if there were minor ones, you agree with the proposition and collorary's statements, right? <hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>

I do Agree with What you had Stated. My point being is that Snipe was basing an argument on what he did not understand or could not follow in your explanation of Physics properties.

Snipes application was on basing Aeronautical Performace Data to explain applied Physics. This is Incorrect

I think my post above clearly stated that Combat manuever performance is based on the Aeronautical design to conteract Applied Physics.

Physics Law is absolute.

If you made any error it was in the way you and snipe presented the initial argument that started the purpose of the post.

My Post reflects the relationship between Aeronautical Design and Applied physics.

Snipe was Focused on a Aeronautics theory, and you were focused on Applied physics.

"The power to Destroy the planet, is insignifigant to the power of the Air Force----Mudd Vader

Great data Mr Mudd! I was searching for stuff like this yesterday, but I only found sustained turning rate on the air craft.

How long you been working w/ jets? I never did get to take the graduate level fluid mechanics class <img src=icon_smile_sad.gif border=0 align=middle> (and they had no real undegrad one). So, unfortunately my knowledge of the intricate details of flight, etc is very limited. I was always kind of into the theoretical side of QM/E&M/mechanics (rigid body mostly). Hopefully some day I'll get some time to read up on some of the other stuff.

I concede that i misunderstood the why's of it all. Not sure i can even see straight after reading all that Xy/Z = blah, blah, blah stuff above.

Feynman, told ya he was a sharp cookie, eh?

Thanx as always senior mudd. I appreciate your proving me wrong, hehehehe.

OK, let me ask a different, but related question. We have two balls, one weighs 1 Kg, one weighs 2 kg. Will the 1kg ball require as much perpindicular thrust to change direction at the same rate as the 2kg ball would?

Or another version of the same question:

If i have a 10lb and a 20lb balling ball rolling by me(paralell to my facing) on the ground, and i wanted them to change their course by 90 degrees- wouldn't i have to kick the 20lb ball twice as hard to get it to travel the same distance at the same rate of acceleration as the 10lb ball?

This is the point i'm trying to get a better grasp on, and apparently i'm poorly communicating it. With the fighter, wouldn't the heavier fighter require more control surface applied force(or vectored thrust) to change direction and overcome it's forward momentum than the lighter one?(all other things being exactly equal).

"Freedom is never more than one generation away from extinction"

Ronald Reagan

<BLOCKQUOTE id=quote><font size=1 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote> This is the point i'm trying to get a better grasp on, and apparently i'm poorly communicating it. With the fighter, wouldn't the heavier fighter require more control surface applied force(or vectored thrust) to change direction and overcome it's forward momentum than the lighter one?(all other things being exactly equal).<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>

I'll rephrase your question:

"Will the heavier F15 require a higher "lift vector( applied velocity) value" to match another F15 with less weight for the same Diameter Turn?

Answer: Yes

How will it do this?

Answer: Applying more Radius velocity to increase the density pressure to generate the lift vector. OR requiring more total wing area to counter the Mass (accelerated G velocity Load) The varible is Thrust, and Lift generation countering Centripedal velocity.

This is all dependent on the same plane and density. However Faster the Degree per second the less capable at a given point will the Heavier aircraft beable to match the lighter fighter in the turn. The limiting factor is the Total Wing area and lift created. Exponentially the G load factor exceeds the Lift Vectors potential.

The centripidal force never changes. What does change is the rate of velocity vector provided by the wing planform and the manuever control deflection to apply the countering force.

The higher the altitude the less density that the Wing planform and control surfaces can create countering Velocity. There fore on my previous posts with the Combat manuever tables demonstrates what the Aircraft are required to do to meet their optimum values at differnt regimes of flight.

An aircraft that depends on Atmosphere density pressure for its Manuever countering force will max perform at the highest density level. That level is the Mean Sea Level at a given temperature.

Higher altitudes and Higher tempertures will degrade the effect of the
total lift velocity vector potential.

"The power to Destroy the planet, is insignifigant to the power of the Air Force----Mudd Vader

Edited by - mrmudd on Aug 14 2004 9:00 PM

I got Snipe's thing a bit wrong too. I was looking at the comparison between the two airframes, and I knew that you'd have to look at the different geometry and such as Mudd pointed out. Dealing with two planes of the same type but different loads, as later mentioned, was teh better comparison to answer the question.

"Some pup"
Nickname by Fenderstrat72

_________________
Evil is evil, no matter how small.

<BLOCKQUOTE id=quote><font size=1 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>
I concede that i misunderstood the why's of it all. Not sure i can even see straight after reading all that Xy/Z = blah, blah, blah stuff above.

Feynman, told ya he was a sharp cookie, eh?
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>

hahaha. Ya, beware of they xyz's <img src=icon_smile_wink.gif border=0 align=middle> They actually aren't bad if you gradually learn 'em (like anything). All at once though, i'm sure they can seem overwhelming.

And ya, Mr Mudd seems to know a thing or two <img src=icon_smile_wink.gif border=0 align=middle>

Thanx Mudd, that was a ridiculously detailed answer.

I am not worthy.

"Freedom is never more than one generation away from extinction"

Ronald Reagan

We are not worthy, we are not worthy. At the end of the day a practical question since the f-15 is not fly by wire does it have less technology to limit the pilot from exceeding 9g, therefore require the pilot to be more aware of the pilots limits versus the computer limiting him.

Snipe and I have gone round on this once or twice, so let me support his original "mistake" ever so slightly (even thugh I always take the opposite side in this argument lol!).


a well worn example:
2 iron balls, same diameter one hollow and hardly weighs anything, one solid and is VERY heavy. Drop them in a vacume, which one hits the ground first? The light one of course, anyone want to debate or is this one too obviouse?
I'll try and get back in a few days but my time is extremely limited these days.

"We sleep safely in our beds because rough men stand ready in the night to visit violence on those who would harm us". George Orwell

Fighting For Justice With Brains Of Steel !
<img src="http://www.fas.org/man/dod-101/sys/ac/atengun2X.GIF" border=0>

_________________
The only time you have too much fuel is when you're on fire.

<BLOCKQUOTE id=quote><font size=1 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>
2 iron balls, same diameter one hollow and hardly weighs anything, one solid and is VERY heavy. Drop them in a vacume, which one hits the ground first? The light one of course, anyone want to debate or is this one too obviouse?
I'll try and get back in a few days but my time is extremely limited these days.
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>

I'm game. Why do you say the light one hits first?

If I recall from a science center exhibit, they will poth hit the ground at the same time. The Apollo astronauts did the same experiment, with the same result. Of course, we're talking gravity here, I'm not sure if things change when you try to change the direction of acceleration.

"Some pup"
Nickname by Fenderstrat72

_________________
Evil is evil, no matter how small.

yeah the Apollo experiment was with a feather vs. a hammer, I wish I had the video. If they were released at exactly the same instant, the feather should have landed ever so slightly first.

"We sleep safely in our beds because rough men stand ready in the night to visit violence on those who would harm us". George Orwell

Fighting For Justice With Brains Of Steel !
<img src="http://www.fas.org/man/dod-101/sys/ac/atengun2X.GIF" border=0>

_________________
The only time you have too much fuel is when you're on fire.

<BLOCKQUOTE id=quote><font size=1 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>
yeah the Apollo experiment was with a feather vs. a hammer, I wish I had the video. If they were released at exactly the same instant, the feather should have landed ever so slightly first.
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>
I'm still waiting on your reasoning for this one.

Are you trying to say inertial and gravitational mass have different values or something?

please explain.

Edited by - feynman on Aug 15 2004 9:44 PM