Originally posted by sonhouse I am not an expert on it but it might work, certainly spin would effect the ball in zero gravity as much as high gravity, maybe more. It might
take more energyt to play that way, don't know. I guess the rebound problem could be taken care of by magnetic boots or velcro though.
With both players aiming in opposite directions their combined torque would can ...[text shortened]... e table vs a positive electric charge on the ball would simulate gravity, what do you think?
About spin - Zero gravity in atmospheric air pressure might do the trick. In free space in total vacuum it is not possible. (No one have mention that either, I know.) But to rely on top spin all the time makes table tennis rather boring. But, it can be done, all right.
About electrostatic forces between table and ball - It does behave in another manner than the gravitational field. Grav field is constant (locally) but electrostatic field is dependent of distance between the table and the ball. I think one get the impression that once the ball touches the table it seems that the balls kind of glues to the surface, perhaps after a few small bounces. I don’t think you get the impression of ordinary full grav table tennis at all.
I enjoy this discussion a lot. One have to think from the beginning again. What forces exist, how do the objects behave in zero grav. Do things behave differently depending of air pressure, no grav or low grav? And such...
Originally posted by FabianFnas About spin - Zero gravity in atmospheric air pressure might do the trick. In free space in total vacuum it is not possible. (No one have mention that either, I know.) But to rely on top spin all the time makes table tennis rather boring. But, it can be done, all right.
About electrostatic forces between table and ball - It does behave in another manner ...[text shortened]... o grav. Do things behave differently depending of air pressure, no grav or low grav? And such...
You are correct of course about the differance between electrostatic forces and gravity but in a spirited table tennis game the ball would be really honking, going so fast that there would only be a small amont of time for the electric force to alter the path of the ball, it would have to have a low force hit to make it stick or such a low angle of attack it would be going essentially parallel to the board which usually does not happen. So did you ever figure out if you heard of Sune, Lotties granpa?
Originally posted by FabianFnas My mass is 60 kg. If I charge for a hit to a 6 kg ball and send it away with a speed of 60 km/h - this will result to sending me backwards with a speed of 6 km/h.
Why? Newtons law of action and reaction! You can't avoid it.
so let me get this straight..if a ball weighing 6kg travelling at 60km/h were to hit your 60kg opponent in the head then he would fly off at 10 km/h and the ball would bounce off him moving backwards at 6km/h?
Originally posted by FabianFnas About electrostatic forces between table and ball - It does behave in another manner than the gravitational field. Grav field is constant (locally) but electrostatic field is dependent of distance between the table and the ball.
This is certainly true for point charges, but the electric field between two charged plates (capacitor) is essentially constant except for fringing effects at the edges. You might be able to have oppositely charged floor and ceilings, to give the effect of "constant" gravity over the table. You'd also need a way to charge up the ball. I haven't given any thought to the field strengths required though. Are we designing a giant "bug zapper" perhaps? 😲
Originally posted by leisurelysloth This is certainly true for point charges, but the electric field between two charged plates (capacitor) is essentially constant except for fringing effects at the edges. You might be able to have oppositely charged floor and ceilings, to give the effect of "constant" gravity over the table. You'd also need a way to charge up the ball. I haven't giv ...[text shortened]... to the field strengths required though. Are we designing a giant "bug zapper" perhaps? 😲
I had already mentioned a way to make the ball with a charge, its called an electret, its the electric field equivalent of a permanent magnet. Its used in capacaitve microphones which negates the need to have a separate power supply, most modern mikes for cell phones and such. It doesn't have to exactly duplicate gravity just get the ball back down on the table. You need to look at the hewlett packard plotters, they have an electrostatic paper holder, its a partially conductive plastic that distributes the charge evenly and keeps it from arcing but it keeps the paper on the platen. It should work.
Hey, good for you! Another candidate game. That would be interesting in zero gravity! But you would be vulnerable if you had to fly across the room to get to another handhold or something because once you launch off a wall you won't be stopping till you whack into a wall or something. Of course you could have a large room filled with a 3D matrix of ropes where you could always have some traction to level the playing field. The rope would partially shield you also. Maybe they should be more like ribbons say 6 CM or so wide so it could be used as a shield if you see someone shooting. That would give you a better chance in the open! It would at least be a safe game, laser pulses would only have to be a milliwatt or so, just enough to activate a sensor like in regular laser tag. Paintball could work too but it would be really messy in zero gravity, if you ever saw how water scatters in the space stations, it takes a while to clean up. So the place would be littered with drops of paint that left the scene of the crime!
Originally posted by sonhouse Hey, good for you! Another candidate game. That would be interesting in zero gravity! But you would be vulnerable if you had to fly across the room to get to another handhold or something because once you launch off a wall you won't be stopping till you whack into a wall or something. Of course you could have a large room filled with a 3D matrix of ropes wh ...[text shortened]... clean up. So the place would be littered with drops of paint that left the scene of the crime!
How about this:
You have a tube, say 1 meter in diameter and say 10 meters long, obviously those numbers would change in a spacestation or orbiting hotel but the idea is the inside surface of the tube is fitted with electrets, permenant electric fields, and you have a rather light ball the size of a bowling ball but it has the same charge so has to keep away from the edge of the tube, at the other end you have pins lightly held in place by some version of velcro or sticky stuff where they are in a pyramid shaped but the stuff holding them are like rubber bands so they can move out of the way when the bowling ball comes careening down the tube, it has to hit the pyramid of pins, which may be spheres, or cylinders and if hit just right, like the spin given to regular bowling balls, will knock all the pins loose from their light moorings and they spin away into a holding net. Any not knocked loose and you get another shot like in regular bowling. The electric fields allows a kind of english to be applied to the ball so it can bounce off the wall and given a spin follow the new course like bowling.
Spacebowl I guess you would call it.
Originally posted by FabianFnas The free space kind of paint ball would be fun!
Yeah, anything where you are in effect, flying. Although some people coudn't do it because of nausea problems. Another game that you do in a large zero gravity volume would be where the players had little backpack air tanks feeding adjustable air jets so you can basically fly around the field where the aim would be like football, kicking, intercepting, aiming for a large hoop that would be the goal. Your players would play only for as long as the air supply held out and have to retire when you get down to 10% air or such so you can get out of the playing field. Of course there would be a contingent of ref's and people watching on the sideline. 3 dimensional football.
Originally posted by FabianFnas §1: It is not allowed to vomit in the helmet.
I was thinking more along the lines of a large room, gymnasium sized, that was filled with breathable air, thats so spectators could watch without having to either have spacesuits on or just watch over a monitor. So the backpack thing would just be ordinary compressed air sufficient to make like a small rocket, enough to manouver around in the game.
Here is a poser for you: games in space.
13 Apr '06 07:12
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