Heavy Sphere Weak Bridge.... Part 2

Originally posted by FabianFnas
No friction assumed, remember. This means no air restistance too...

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 mtthw
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.

Something to think about...

Originally posted by AThousandYoung
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.

So what you are saying is to solve this problem i need a racket and a killer slice?! ;o

Originally posted by wolfgang59
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.

Maybe its so much fun because we actually know the answer.

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...