Ah - hi tugboat.
Yes I do know the answer, but it should be kept an aerodynamical and gravitational secret.
However, if that ping-pong ball is played on a train moving at, say 70mph through a station, does the bloke on the platform think - "Blimey, that ball was going 30mph in one direction, and 100 mph in the other" ?
They are both correct. Good old relativity.
I would put my ping-pong ball at the Legrand point, between the Earth & our Moon, where gravity from both bodies are equal.
It should rotate for nearly ever, until small gas molecules get in the way in a few thousand years time.
Or fill one with helium through a small hole. The do try to hover a bit.
The best bet is to fill one with 5th November stuff, get the kids to stand back, and light the banger fuse.
The thing fires upwards, seems to hover, then dissapears in a puff of smoke & sparks.
Not reccommended to all.
A ping pong ball will hover a decent hair-dryer.
Oh dear, am I anywhere near correct here ?
Cheers for the question,
Bob.