What is the proper air pressure for a soccer ball?
According to FIFA, The size of a soccer ball is roughly 22 cm (8.65 inches) in diameter for a regulation size 5 ball. Rules state that a size 5 ball must be 68 to 70 cm in circumference. Averaging that to 69 cm and then dividing by π gives about 22 cm for a diameter.The ball's weight must be in the range of 410 to 450 grams (14 to 16 oz) and inflated to a pressure of between 0.6 and 1.1 bars (8.5 and 15.6 psi) at sea level.Any more pressure and you risk lop-siding the ball (aka uneven) because the “inside bladder is a soft latex rubber bladder) and the outside leather stitches could tear.Not enough pressure and the ball doesn’t kick or bounce right. If ever there was a sport where the pressure needs to be just right this is it. Have you ever seen a goaly kick the ball from his end all the way across the field to the other goaly??? properly inflated it can do that.
How do I kick a soccer ball with power, distance, and height?
To get height: As others have said, you need to hit the ball with your foot below the center to raise it. But you'll also need to lean your body back some so you can direct your kick upwards. Make sure you plant your plant foot a little further back than you normally would for a lower driven shot, but not so far away that you have to stretch to make contact, as this will cost you power.To get power: You want to hit the ball as close to centered as possible, so your entire instep (feel for it, it's the hard bone on the top of your foot, down from the ankle but up from the toe phalanges) contacts the ball at its middle. The most important thing about power is to keep your foot "locked" - point your toes down and stiffen your ankle so you hit the ball with a sturdy foot. Any "banana foot"-like action will soften your contact. Make sure to follow through, and practice your motion so you can do this quickly for maximum impact.To get distance: Master both of the above, and your shot will go pretty far. For extra distance, try to hit the ball at a trajectory of roughly 45 degrees to maximize horizontal distance traveled (of course, the wind/air resistance in general will have some bearing on this)
How can I model the forces required to hover a ping pong ball in an open-ended tube using air pressure with an output as the distance from the air source?
By your description this sounds like the ball is encased in the tube and only the vertical dimension is in question.Since the ball is sitting at a standstill (acceleration = 0) the upward and downward forces must be equal. Balance the upward and downward forces on the ball. Downward is gravity and F=ma; in this case mg, where m is the mass of the ball and g is gravity.The upward force is the friction between the air and the ball. This component is C(A/2)d(u^2), where C is the coefficient of friction, A is the surface area of the ball, d is the density of air, and u is the velocity of air coming from the source. Here's your equation:mg = C(A/2)d(u^2)This is the basic model from which I would start. There are other factors you can work in such as friction between the walls of the tube and the air, the pressure drop between the inlet and outlet of the tube and it's affect on air density, and if you care to put in the horizontal effects they are probably significant also.Interesting problem. Good luck.
What would happen if I filled a soccer ball with helium?
It will become around 0.7% lighter. And deflate quickly.Ballpark figures will suit the topic well. A soccer ball has a volume of around 1.4 liters but the overpressure is around 1 atmosphere so the air inside is equivalent to 2.8 liters, which weigh 3.3 grams. The same volume of helium weighs 0.5 grams, so the difference is 2.8 grams.Meanwhile, regulation states that the ball (with air, presumably) should weigh 410–450 grams, so the weight reduction is negligible compared to the allowed span.And since the helium molecule (i.e. the helium atom) is much smaller than the nitrogen and oxygen molecules that air consists of, it will diffuse quickly through the rubber bladder in the ball, so you will have to inflate it quite often.
Questions about BASEBALL?
It would be impossible to answer all of those questions in a few brief paragraphs. Might I suggest using teh Internets to find your information? You can begin here: http://en.wikipedia.org/wiki/Baseball Good luck.
If I drop a golf ball and a bowling ball simultaneously from same height above the ground, what will happen?
They will hit the ground at the same time. The reason for this is because although gravity is pulling harder on the bowling ball, the bowling ball is harder for gravity to move. Gravity is pulling less on the golf ball, but it is easier for gravity to move. The funny thing about this is that both of those factors cancel each other out. Without air resistance, all objects fall at the same speed. But, if you were to put a parachute on the golf ball, it would fall more slowly than the bowling ball due to increased air resistance.