Assume a Frictionless world that has gravity. What will happen to a sphere if you drop it into a half circle ramp that is equal distant on both sides. I don't know the answer. I can only speculate that the sphere will either 1) continue rolling back and fourth forever, always reaching the same height, or 2) gravity will pull it down until it comes to rest at the bottom on the circle. Does anyboy know what happens? Or is something that we may never know the answer to. Can we have a frictionless environment if we have gravity? Are the two forces linked? Just curious. ------------------ humble, but hungry.
If the surface was REALLY frictionless then I would presume that the sphere would continue to roll forever as long as the gravity is constant. ------------------ Houston Rockets Forever!! In Rudy We Trust
Using the law of conservation of energy, scenario 1 is correct. Potential energy is the product of an object's height above a reference point and its weight. As the sphere rolls down the ramp, the potential energy is converted into kinetic energy, or the energy of motion, Right at the bottom of the ramp, (assuming this is the reference height and it = zero), then all of the sphere's ebergy is now kinetic. Since there is no forces of friction acting on the sphere, then the kinetic energy must equal the original potential energy. mass X height = half times mass times velocity squared. So what happens to to the sphere now? It has all this kinetic (motion energy), and in order to maintain the conservation of energy, it will keep moving, up the ramp, until it stops, at which time kinetic energy will be zero again, and all energy will be potential. If there has been no losses due to friction on the upward(or downward) path the the height reached must be the same as the starting height. Of course, this assumes there were no other forces, like chemical or electrical, acting on the sphere. ------------------ Current Rocket's Salary & Contract Info [This message has been edited by davo (edited August 15, 2000).]
Thanks guys, I've been having trouble picturing a frictionless environment and how it would work. The scientific rules are what I needed to get me past this mental block. Now I can move on. It was troubling for a while. ------------------ humble, but hungry.
So I've been watching quite a few space shows...on the science channel or whatever show that talks about how the universe works. Very fascinating subject. So I started thinking about time and the speed of light and the theory of relativity. I know very little about physics and try to find articles that explain it in a easy-to-understand manner. Quite a few of them out there. But something that gets me is traveling at the speed of light. Supposedly, based on physics, traveling at this speed, time would stand still. So I started thinking about that rule applying to any object traveling that fast...but what about light itself. Does light recognize time? I mean it is traveling at the speed of light. So shouldn't time stop for light particles...maybe meaning they are infinitely young and old? I'm tripped out. And no, I'm not on anything right now. Just maxed out on Michelle Thaller, Hakeem Oluseyi and Phil Plait.
The academic world of pre-60s physics is insane when you consider all they had to work with is math, some basic experiments that broke down into universal constants, and a helluva lot of imagination. Quantum physics sprouted from the double slit experiment? I mean, I get what it explicitly means but I can't pretend to understand or comprehend its impact and what came from it...
Agreed I am still fascinated how we go from E=MC^2 . . . . to Nukes Understanding the equation is one thing. . . . . How do you leap to applications . .. MIND BLOWING Rocket River
From what I recall from my youth (did you say ute?), photons don't experience time (or distance). They're also massless because if you have anything traveling at the speed of light with mass, it would have infinite energy (E=mc^2, special relativity, twin paradox, and all that - Lord, it's been a while).
Last video is best at covering quantum field theory and how it's currently the best theory at describing reality.
I thought this was kind of amusing - gravity as a side effect of time dilation. also... [Forbes]How Do Photons Experience Time?
If there is no friction, the sphere won't roll at all, it will just glide along the ramp. It should do it forever as the potential energy is converted to kinetic energy and then right back to potential energy on the other side, to answer the original question from 22 years ago. Basically, what davo said, but with the addendum that the sphere would not roll. I am not enough of a physics nerd to tell you whether or not the changes in direction of the sphere would create spin due to inertia/angular momentum or whatever.
The problem begins when you try to re-conceptualize time by challenging your senses (time it takes for light to hit your eyeballs) only to question how we conceptualize space. Space, time, and spacetime...don't really know all three.
