well, not fall but roll down an incline.
maybe I am the idiot here, but I thought we were all taught that the mass is taken out of the equation when calculating acceleration in falling and rolling objects.[/u]
Clearly this is no the case. take two like size objects with 2 different masses and the heavier one will always roll faster, and accelerate faster too.
this is one of the premisis that our machine uses.
in the initial event they will but both will attain terminal velocity of the same speed, no?
i think that yes, they will reach the same speed, but i did this expirement, and wow, it is a huge difference in speed, especially when you do it in a circular motion and apply the dynamics of angular velocity to it, then the heavy one really surpasses the lighter one.
Cam
Quote from: cameron sydenham on May 12, 2008, 12:48:15 PM
well, not fall but roll down an incline.
maybe I am the idiot here, but I thought we were all taught that the mass is taken out of the equation when calculating acceleration in falling and rolling objects.[/u]
Clearly this is no the case. take two like size objects with 2 different masses and the heavier one will always roll faster, and accelerate faster too.
this is one of the premisis that our machine uses.
That's interesting. You are repeating the famous experiment by Galileo. There is a myth that Galileo dropped objects of differing weights from the Tower of Pisa. Historians doubt this actually happened, but what we know for sure did happen is that Galileo conducted many experiments with balls and ramps. The consistent result was that balls of differing weight would always arrive at the end of the ramp at the same time.
Your results are at odds with this. Could you describe your experiment? What kinds of objects did you roll. What was the ramp like?
that is interesting, i read something about that yesterday. here is what i am doing. take a pvc pipe as the medium, cut into 3 or 4 different exact lengths. leave one hollow, and fill the other 3 with different material, i am using jb weld, liquid nail and a metal rod in the last. each one rolls down any incline at different speeds. I also did this with a brass ball the same identical size of a lighter ball, .... i have done with alot of different things, same result, the heavier one always wins.
the way i understood gallileo was he was watching how far the rolled, i was unable to find any where that he "raced" them. i could be wrong but in my expirements, on a slight incline, the heavier one always wins.?!!
i cut and pasted this from http://www.batesville.k12.in.us/physics/PhyNet/Mechanics/RotMechanics/fall_slide_roll.htm
If you "race" these objects down the incline, they would definitely not tie! This is because Newton's Second Law for Rotation says that the rotational acceleration of an object equals the net torque on the object divided by its rotational inertia. (Net torque replaces net force, and rotational inertia replaces mass in "regular" Newton's Second Law.) The net torque on every object would be the same - due to the weight of the object acting through its center of gravity, but the rotational inertias are different. This means that the solid sphere would beat the solid cylinder (since it has a smaller rotational inertia), the solid cylinder would beat the "sloshy" cylinder, etc. The hoop would come in last in every race, since it has the greatest moment of inertia (resistance to rotational acceleration).
Quote from: cameron sydenham on May 13, 2008, 11:30:51 AM
that is interesting, i read something about that yesterday. here is what i am doing. take a pvc pipe as the medium, cut into 3 or 4 different exact lengths. leave one hollow, and fill the other 3 with different material, i am using jb weld, liquid nail and a metal rod in the last. each one rolls down any incline at different speeds. I also did this with a brass ball the same identical size of a lighter ball, .... i have done with alot of different things, same result, the heavier one always wins.
the way i understood gallileo was he was watching how far the rolled, i was unable to find any where that he "raced" them. i could be wrong but in my expirements, on a slight incline, the heavier one always wins.?!!
i cut and pasted this from http://www.batesville.k12.in.us/physics/PhyNet/Mechanics/RotMechanics/fall_slide_roll.htm
If you "race" these objects down the incline, they would definitely not tie! This is because Newton's Second Law for Rotation says that the rotational acceleration of an object equals the net torque on the object divided by its rotational inertia. (Net torque replaces net force, and rotational inertia replaces mass in "regular" Newton's Second Law.) The net torque on every object would be the same - due to the weight of the object acting through its center of gravity, but the rotational inertias are different. This means that the solid sphere would beat the solid cylinder (since it has a smaller rotational inertia), the solid cylinder would beat the "sloshy" cylinder, etc. The hoop would come in last in every race, since it has the greatest moment of inertia (resistance to rotational acceleration).
I think you are correct about the weight distribution thing. That can affect rolling. But different solid spheres should get to the end at the same time.
Quote from: utilitarian on May 13, 2008, 12:25:49 PM
Quote from: cameron sydenham on May 13, 2008, 11:30:51 AM
that is interesting, i read something about that yesterday. here is what i am doing. take a pvc pipe as the medium, cut into 3 or 4 different exact lengths. leave one hollow, and fill the other 3 with different material, i am using jb weld, liquid nail and a metal rod in the last. each one rolls down any incline at different speeds. I also did this with a brass ball the same identical size of a lighter ball, .... i have done with alot of different things, same result, the heavier one always wins.
the way i understood gallileo was he was watching how far the rolled, i was unable to find any where that he "raced" them. i could be wrong but in my expirements, on a slight incline, the heavier one always wins.?!!
i cut and pasted this from http://www.batesville.k12.in.us/physics/PhyNet/Mechanics/RotMechanics/fall_slide_roll.htm
If you "race" these objects down the incline, they would definitely not tie! This is because Newton's Second Law for Rotation says that the rotational acceleration of an object equals the net torque on the object divided by its rotational inertia. (Net torque replaces net force, and rotational inertia replaces mass in "regular" Newton's Second Law.) The net torque on every object would be the same - due to the weight of the object acting through its center of gravity, but the rotational inertias are different. This means that the solid sphere would beat the solid cylinder (since it has a smaller rotational inertia), the solid cylinder would beat the "sloshy" cylinder, etc. The hoop would come in last in every race, since it has the greatest moment of inertia (resistance to rotational acceleration).
I think you are correct about the weight distribution thing. That can affect rolling. But different solid spheres should get to the end at the same time.
Hmmmmm, I could be wrong-I have been before, but I thought this was only true in a vacuum, because once air resistance is factored in the heavier should be less affected????
It is well known that different masses can roll down an incline slower or faster, this is due to how how the mass is distributed in each shape. Different shapes have different moments of inertia
Yes, but didn't Galileo measure the time identically shaped and sized objects
of different weight rolled down the same ramp?
That's the Galileo experiment we replicated in high school, and the one I recall from my
history lessons.
The point was that two equal sized balls of different weight still fall equally fast.
And a variation of the same experiment shows that two identical masses of
different shape and/or size, such as for example a ball of lead and a leaf of paper
both weiging in at one kilogram do experience different air resistance and mass
distribution which causes their drop speed to differ.
Right?
So if that "law" holds, two identically sized and shaped cylinders with identical
relative mass distribution should also fall (and also roll?) at the same speed,
because they experience an identical acceleration due to identical gravity effects.
And if the weight as wel as size and shape of the cylinders is identical, but
the distribution of mass over this body is different in one of the cylinders, they
will indeed roll down a ramp or fall at different speeds.
And of course in rolling down a ramp the surface friction comes into play as well,
whereas a falling object only experiences air friction which is much lower.
That said, if you have a setup that appears to be able to self-run somehow,
and it is based on your different mass cylinder idea, then I'd certainly like to
hear some more about it. sounds potentially interesting. :)
I can tell you what I know about mass and speed from my childhood days. When I was a little kid, I was in cub scouts and my best friend's dad was the scout leader or whatever. When it came time for the pine derby, my friend always won. (The pine derby was a race down a curved ramp with small unpowered pine wood toy cars about 6-7 inches long. Why did he always win? His dad showed me. It was mostly graphite for friction on the wheels and as much lead weight as possible to still be "legal" weight. Of course, the less wood for the body there was, the less air friction and the more weight available for more lead weight.
The only force the cars used was gravity. (Another unidirectional force similar to CF? Gravity isn't adjustable however.) The point is the heaviest / aerodynamic car always wins. Maybe fat kids win those box car derbies more than skinny kids? :D
the cub scouts new about the fact that the heavier the object was, the faster the cart went, all else contstant. the guy i am representing that is building an "over unity" motor has also built a "box cart racer". we can easily demonstrate that by adding more wight to the cart, the faster it goes.
@koren- i spent all afternoon with 2 identical pvc cyllinders, one hollow, one with a metal rod through it, one with liquid nail in it( which took forever to dry) and for kicks, i filled one with water and froze it,
each one rolled at different speeds.
before i started, i "raced" each one down the incline all hollow and they were identical in accelleration and final speed as observed with my naked eye.
the slope i used was a lond wooden buffet table about 6-8 feet lond, i placed a fat book about 3 inches under one end and went racing.
the way i raced them was by placing the 2 or 3 or 4 cyllinders pointing down the hill behind each other, then repeat the process alternating a different one in the front each race. i would hold my finger in front of the front one and watch. then repeat the process with a different one in front. they all pretty much stayed together all the way down.
then when i made the modifications to the pvc cyllinders did the same race. if the heavy one was in front, it would leave the others behind. if the light was in front, it would get pushed.
here is a a real funny one for you bigface. if you have two identical wheels, both of the same mass, but one has the mass around the perimiter and the other is equally distributed like a disc, wich one goes faster now???
now one step even further, the anser to the last statement is opposite in a Centrifugal environment.!!!
koren, all i am talking about is rolling down an incline, falling is different. the all fall at the same rate. rolling though......
If you're talking to me, my name is not Koren. ;)
Anyway, yes, there can be a difference in rolling speed,
but does that really have to do with the Galileo experiment?
I think that with increased weight comes increased friction,
and that can influence rolling speed.
But that doesn't change the fact that they fall equally fast,
and that gravity 'pulls' them equally hard, thus accellerating
them equally. Galileos observation still seems valid.
So you may have a point there, in that rolling down a ramp is
not the same as falling vertically. In the ramp situation friction,
mass distribution, rotational momentum, etc all play along in the equation,
whereas in a fall it is mainly friction and gravity.
Can you please drop some more clues in respect to the alleged motor
based on this? sounds interesting.
well stated. as far as comparing to gallileo, i am not exactly sure if i am contradiction him or not. all i can say is this, when i boserve 2 identical "wheels" with a modification to thier weight, the heavier one will always roll faster. the only thing i came up with was this, if the incline was too aggressive, they seem to "fall" more than "roll." so i think that the fact that when i observe the actual rolling of the 2 masses, someone else brought up the rolling enertia or something, this is why the 2 roll at different speeds.
as far as our motor, i posted a month or so ago about a motor that we are working on that with an input or @2000 watts, we can possibly get out @200 hp and 650 lb of torque a 1000 rpm / opm(orbits per minute) this went over like a lead ballon for obvious reasons, conservation of energy, newton and so on.
if you take into consideration that a motor(the one we are building) can actually use the centrifugal force that in all motors is a biproduct and "feed" it back into the center, the amount of additional power is remarkable.
for example, if you take an 8 lb mass and rotate it around a central point with a radius of 6 inches and a velocity of 1000 rpm, if that motor were to "break off", it would have a "weight" of 1346 pounds.
we do not let it "break off" we have found a way to utilize this added force/ energy
now you can take that 1346 and turn that into torque = 682 lbs of torque
and that turns into hp of 129hp. all at 1000 rpm.
the law of conservation of energy, newtons laws all play a major part on why our motor will do what we intend it to do.
equations for above are Cf= m x r x rpm ^2 x .000341
tq= Cf x r
hp=tq x opm x 2 x pi divided by 33000
Cam
It has always bothered me that the attraction of every object in the universe to the others is dependant on mass, and yet when we drop objects on Earth mass is not supposed to impact speed.
If the attractive force between objects increases (via increased mass), wouldn?t also their acceleration toward each other and final velocity?
It has always been my suspicion that in practical terms Galileo was correct ? but only because the objects we can test with are so small relative to the mass of the Earth as to make them almost inconsequential. But what if we used a huge mass, the size of a mountain?
This is probably just an academic discussion because I doubt we could ever be working with large enough objects on Earth to make any difference.
But, what if a ramp (hill) somehow amplifies the mass difference in force applied by gravity? Maybe a kind of lever.
Regards,
jeffc
i kind of thought that myself, that the incline might somehow magnify and spread out the change. who knows.
another group that knows the heavier the faster = the Olympic committee, bobsled for example, hmmm but here there is no wheel, just sliding down an incline.