Quote:
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Originally Posted by artdutra04
Ken and all the others are correct. If you want proof, see this video clip. They mounted a fan on top of a skateboard, and as the skateboard began to gain velocity, the paper underneath the skateboard was pulled backwards at the same velocity in the other direction. The skateboard continued to accelerate, just as normal.
Here is another good way to think of this problem, as it was posted by an unregistered user on another forum: |
hmm.. well although this wont mean anything, there is no proof that the paper was moving at the same speed... actually, it wasnt.
i have no idea how i should word this, but well...
you are all saying that the belt is moving at the same speed as the plane but the plane moves forwards. wheels or not, if Vplane=-Vground(in this case belt), Vplane+Vground=0. which means the plane does not move. ignore the wheels completely. the plane is on blocks attached to the plane.. the plane has unlimited thrutst so this does not affect anything.. (the belt also has unlimited thrust... or torque, if its a conventional conveyorbelt. so that also doesnt change anything)
so at first the plane is standing still. so Vplane=0.... which means Vbelt=0 also
now the throttle is pushed on the plane.
so Vplane relative to the air = 1
except since Vplane =1, Vbelt=-1... except the blocks and belt have enough friction ............................
or waaaaaaaaaait a second...... Friction is changed only by normal force...(since the coefficients dont change)....
Crap.. a BIG point everyone including me has failed to point out.... Force of Kinetic friction is always constant no matter how fast the two planes are rubbing right?darn.... so basically the wheel's bearings.... no matter if they are spinning at 1rpm or 287346821736498723649876rpm, the force of friction is the same right?... so the conveyor belt... no matter how fast it spins, it can not stop the plane...
aha. and no, noone mentioned that before, yes people have said that the friction was negligible but noone backed that up. i think im not the only one that was under the impression that the faster you......
or.... darn it. lost it.... anyone continue on that proof?
till then..
but yea. well i guess this shouldnt be called a physics problem cuz so much is ignored.... and yea. the plane does go up i guess. or does it..
all these people have examples of experiments.... even the video.. but noone has created a "true" conveyor belt... so those experiments are flawed. SO confusing... but this problem is a neverending pit of trying to prove the other wrong.