Maybe in some sports you can, but in most sports that is considered a "foul play" or "unnecessary roughness".
A variety of balls for sports can in most cases be found in local sport stores. Otherwise Amazon and eBay provide a comfortable way to order balls online.
It depends on which balls. Most sports have a defined size and weight for balls. If the ball falls outside these parameters then they are probably illegal within that sport.
Hockey the most as I know
Well most of the sports use gravity especially the ones when you have to not touch the ground at some point. Sports like darts don't use gravity because there feet are always on the ground.
what kind of question is that? You are silly boy
I see DDH on most Dunlop sports equitment eg Dunlop DDH golf balls.
they are round and therefore are the most reasonable object to use due to the fact that they do not take any unexpected bounces.
Almost every kind of sport, but football, volleyball, basketball are the most popular.
AFL (Australian Football League)
There are many sports that Scott Sports USA might host. The most popular sports that are hosted are biking and motosport events, in addition to different winter sports.
They played a lot of different kind of games but the most played was catch the balls. They played this with balls from a pig.