Why do people put tennis balls on trailer hitches?
823434
to keep the hitch from rusting from weather exposure.
76423
Dimples first appeared on golf balls more than 100 years ago when golfers discovered that balls which had been scratched or roughed up traveled further than smooth balls. Dimples are what gives a golf ball lift. They create two layers of air going around the ball. The top layer is going faster than the bottom layer which creates turbulence. This reduces the drag and allows the ball to travel further than a smooth ball.
727300
velcro hats you chuck balls at
962543
cellotape some tennis balls to your stomach!!
124492
nope, just an urban legend. Same as people with pickup trucks driving with the tailgate down to reduce wind resistance (that one was actually proven to take more gas by the guys on Mythbusters)
191246
I believe what you are looking for may also be called the Diamond Hitch.  Link below shows diagram and has how-to explanation:
772547
Increase your elevation or find a court with less gravitational force.   It's  a physics thing.
599146
Probably it's so you can roll over without falling off it and waking up.
10553
you are speaking of the collision ball apparatus and not the Gravesande Apparatus I assume.\n\nThe reason has to do with newton's law...\nThe force transfers from one end to the other and causes the same MASS to move the same distance (minus friction)\nif the first ball was twice the MASS of the rest of the balls, then dropping that one ball would cause 2 balls on the other end to move.. and conversely, dropping 2 smaller balls would make the one larger ball move.\n\nA = F/M
491710
because they wouldn't roll. unless \nyou meant so they could just slide...\nno no that is way too difficult.\nwhy don't you invent a sport with square balls?
936014
According to 60 Minutes it is a racket they manufacture them selling them over and over.  Nice thought though!  God Bless You and The Southern People.
510674
Its all aerodynamics. Different angle of incidence of air flow on different curvatures give much more flight and movement to a golf ball. This adds more thrill to the play
1146675
The fuzz slows down the ball in flight, keeps it from bouncing too high, and lets  the racket get a better "grip" on it. A perfectly smooth ball would travel so fast  and bounce so high that the game would be unplayable. Also, with a smooth  ball, it would be much more difficult for the player to control the direction of  the shots.
163316
Ball bearings help ease the friction in wheels when they are turning.  It makes it easier for the wheel to turn faster.  They are used in things like roller skates.
159027
Are you talking about bumping? You use the arms because your "platform" is larger, wider, flatter than the hands. This helps with accuracy and control. When standing you are able to easily carry a ball on your arms or platform. Try this on your hands. Not so easy.
331438
i dunno pull on them i guess, i was born lucky, my wife says"you got balls you have to haul in a dump truck" no joke there big and long, they hit the water when i take a dump, i wouldnt mind a smaller pair.
1165384
I'm well-qualified to answer this question because I'm a Mechanical Engineer as well as a nationally certified Tennis Instructor.\n\nThe are two reasons why a tennis ball bounces. First, the rubber from which the ball is made is naturally resiliant (bouncy). Second, the air inside the ball is pressurized at 15 psi (pounds per square inch), which causes the ball to bounce at the correct height.\n\nThe way the 15 psi air gets inside the ball is very simple. Be advised, it is not injected into the ball. Instead, the two halves of the ball are cemented together while inside an environment (a room) that is already pressurized at 15 psi.\n\nIf the balls were then packed into a non-pressurized container, the air would slowly seep out because it would push against, and expand, the ball's porous rubber. And, in just a few days the balls would become unplayable, due to their low bounce, even though the felt nap covering the ball was unused and in perfect condition.\n\nSo, instead, the balls are packed into the container while in the same 15 psi pressurized environment. This way, the 15 psi air inside the container counteracts the 15 psi air inside the ball, and the air inside does not seep out.\n\nIf you do not play tennis with the balls, as mentioned previously, they will become unplayable in just a few days even though they look brand new.