Originally posted by FabianFnasStrictly speaking most air resistance isn't friction, it's pressure. You can actually calculate a lift force on a ball if you assume completely inviscid flow.
No friction assumed, remember. This means no air restistance too...
But as has been pointed out, this isn't going to get you anywhere in this particular problem.
Originally posted by mtthwSomething to think about...
Strictly speaking most air resistance isn't friction, it's pressure. You can actually calculate a lift force on a ball if you assume completely inviscid flow.
But as has been pointed out, this isn't going to get you anywhere in this particular problem.
Originally posted by AThousandYoungSo what you are saying is to solve this problem i need a racket and a killer slice?! ;o
A forward rolling sphere, if it were flying in the air, would curve downwards. To go upwards you need to make it spin in such a way that it would come rolling back to you if it hit the ground.
Originally posted by wolfgang59Maybe its so much fun because we actually know the answer.
I cannot believe that some of you are being suckered into this anti-grav invention!!
The ball weighs the same when moving as it does at rest. The downward force is the same.
The argument is that there will be a centrifulgal force upwards that will make the ball lighter, but there will equally be a centrifulgal force downwards that will cancel it out. The best you may achieve is that it might be a moment before the bridge collapses.
Heh, this is such a relief after all those difficult trig questions...