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# Stationary Ball Game

Move the players to avoid spectator neck injuries
 (+4) [vote for, against]

Watching tennis on TV is easier than sitting beside the court turning your head this was and that for hours.

Clearly to avoid spectator neck injuries the e.g. tennis court should be moved relative to the ball. Spectator stands and referee can be lifted slightly above the moving plane of the court.

The ball itself would be suspended from a metal pole that could be raised or lowered depending on trajectory, but the relative horizontal motion is achieved by moving the court itself.

For example: a player runs toward the tennis ball and the impact velocity with the racket is calculated. As soon as the ball is about to be struck the court moves at e.g. 80-120mph to take the player who struck the ball away from it*.

* This may require slightly different tactics to the game.

 — bigsleep, Aug 10 2016

https://www.youtube...watch?v=mqPytl80abc you could just do it Matrix Pingpong stylee.. [not_morrison_rm, Aug 11 2016]

https://en.wikipedi...3Keating_experiment [hippo, Aug 11 2016]

[+] pastry proferred - I woke up this morning with a stiff neck that goes from elbow to mid back.
 — FlyingToaster, Aug 10 2016

This could work in micro-gravity. The ball stays stationary and how your racquet impacts it determines where you touch down on the semi-spherical court.
 — 2 fries shy of a happy meal, Aug 10 2016

//could be raised or lowered// Shurely the court should be raised and lowered, not the ball?
 — pocmloc, Aug 11 2016

 // Shurley //

 Sp. "Shirley"

 // a stiff neck that goes from elbow to mid back. //





<Concludes that [FT] is either (a) an amoeboid Zingatularian, or (b) a direct descendant of John Merrick. Or possibly both.>
 — 8th of 7, Aug 11 2016

But who is to say that this is not what happens already?
 — hippo, Aug 11 2016

 No-one. Relativity means that an observer cannot determine if "the train leaves the station, or the station leaves the train" (Einstein's words).

 This is valid irrespective of where the observer is*.

*Apart from when they're under the train, in which case no further observations are possible.
 — 8th of 7, Aug 11 2016

Yes, there's no difference between thing A moving with respect to thing B and vice versa, except that only one of thing A or thing B will experience acceleration resulting from the rapid changes of velocity - and the concomitant time-dilation effects.
 — hippo, Aug 11 2016

If the masses of the two units are comparable, even the acceleration won't tell the observer much.
 — 8th of 7, Aug 11 2016

So the answer is surely to install very accurate clocks inside the tennis ball and at the side of the court? Then, analysis of the time-dilation effects will show which is accelerating relative to the other.
 — hippo, Aug 11 2016

//who is to say that this is not what happens already?// Well if it is happening already, the metal pole is well concealed or camouflaged.
 — pocmloc, Aug 11 2016

Thought this might be an idea for rolling up office papers and throwing them around.
 — xenzag, Aug 11 2016

 So, really we really need a invisible pole detector, to catch out the angels/gremlins/monads/dark matter running the place.

With a retrospective function would could observe the rod swinging from the Book Depository on its way towards Dealey Plaza...
 — not_morrison_rm, Aug 11 2016

 // analysis of the time-dilation effects will show which is accelerating relative to the other. //

 Observer/clock A will detect no local time dilation effect as their clock is within their frame of reference. They will however detect a timeshift effect by comparison with clock B. They will conclude that it is clock B which is accelerating.

It is therefore necessary to postulate the existence of Observer C, also equipped with a clock, independant of both A and B. Their task is to keep an eye on the overall time and tell Observers A and B if the pubs are open yet.
 — 8th of 7, Aug 11 2016

I don't see it like that. You can tell which clock has moved relative to the other when the clocks are reunited. If you have two clocks, put one in an aeroplane and fly around with it for a bit, then reunite the two clocks, the one that was in the aeroplane will have lost time compared to the one you left on the ground. The only difference between the two is that the clock which was in the aeroplane has experienced acceleration.
 — hippo, Aug 11 2016

 // You can tell which clock has moved relative to the other when the clocks are reunited. //

 You can tell that the clocks have moved at different velocities, BUT (and this is the important bit) what you can't do is detemine which clock has moved, when, where, or how fast. You can deduce a range of possibilities for trajectories based on (i) the elapsed interval between comparisons and (ii) the accumulated error between the two clocks, but that's it.

This is Relativistic, not Newtonian, physics. Yes, it's non-intuitive. Don't make us do math at you.
 — 8th of 7, Aug 11 2016

Yes that's fair - but you don't need to be patronising. If, when they're reunited, clock B is behind clock A you can say that clock B has been subject to greater acceleration or gravitational forces, but nothing more about what has happened to it.
 — hippo, Aug 11 2016

 // you don't need to be patronising //



This is the halfbakery ....
 — 8th of 7, Aug 11 2016

"In sports news today, the first ever stationary tennis match game was called off as the players and fans were injured by the court accelerations experienced during the opening serve volley. The International Tennis Federation blamed a math unit conversion error for the injuries, and opened an inquiry as to the game developer's understanding of inertia. All advertisers have pulled out completely, except for Jolt Cola."
 — RayfordSteele, Aug 11 2016

Super Monkey Tennis Ball.
 — calum, Aug 12 2016

 Confining the game to an ordinary, 2-dimensional tennis court was clearly a mistake.

 Stationary tennis on a curved surface could prevent catapulting the players off their feet - imagine a half-pipe that rotates back and forth. The acceleration would mostly be tangential to the surface, and players might actually be able to stay on their feet.

The jerk when hitting the ball might still pose a problem though, to which I suggest players should hit the ball really really hard.
 — mitxela, Aug 12 2016

 I like this as a processed version of regular tennis (with grunting!) It could be done with computerized jiggery pokery. The ball is kept in the middle of the screen and the entire environment surges back and forth into view. Your angle of view and what is seen past the ball would change, perhaps very quickly. Field of view would remain constant while the ball was in play but swivels to show sky, ground, or possibly from directly behind the ball in its trajectory - seeing the player and her racquet bloating to fill the screen as you rush towards it.

You might need some extra cameras when initially filming the game. You might need to add a loud soundtrack to keep from getting sick when you watched it.
 — bungston, Aug 14 2016

 A very fast camera-equipped micro-drone could show the game from the ball's point of view.

The ball itself spins, so a ball-mounted camera is impractical. But a fast drone could hover a metre or so above the ball, tracking its position and predicting its trajectory via off-board processing.
 — 8th of 7, Aug 14 2016

The method doesn't allow for spins. What's needed is to let the play happen in the usual fashion, and move the audience around.
 — FlyingToaster, Aug 14 2016

Maybe just chairs that twist back and forth fast enough to follow the ball? No neck injuries could ever result from that...
 — RayfordSteele, Aug 14 2016

The solution, shirley, is to replace all ball sports with ping-pong. The usual arrangement is to have the A4- sized table sitting in the middle of a huge arena with tiered seating. In this way, viewers do no have the move their heads by more than a few arc-seconds for the entire match, even if they remain awake.
 — MaxwellBuchanan, Aug 14 2016

[8/7] Like a sharp funnybone twinge that radiates up, through the shoulder, dallies at whatever tendon that is in the neck, then plunges down past the bottom of the shoulder blade. Spending a few days as an orangutan should cure it.
 — FlyingToaster, Aug 14 2016

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