Physics Misconceptions in Cartoon Form!
In keeping with my mini-leitmotif of commenting on webcomics, I present this series in progress (and maybe concluded) over at Dinosaur comics.
Basically, T-Rex has realized how transcendently awesome it would be to have an infinitely long hill down which to skateboard, and to have this all inside your apartment! Unfortunately, he hasn’t taken physics into account, and all his dreams come to naught.
What Dr. North (and yes, it’s a real Ph.D.) hasn’t mentioned explicitly is that this is a sneaky reformulation of the Airplane on a Treadmill problem. Maybe understanding why this won’t work will help people understand why the plane will still take off.
Still open: Snakes on a Plane on a Treadmill.
Wow, I’d never run into the “airplane on a treadmill” problem before. Fascinating stuff!
When the “airplane on a treadmill” problem first made the rounds, my response was, “The airplane will take off because Jack Bauer is at the controls and Chuck Norris is pushing.”
I agree with Patricia, this is pretty interesting.
Maybe I’m not thinking clearly, but it seems like the skateboard-on-a-treadmill problem *could* work:
There’s an equilibrium point where the frictional force from the bearings matches the gravitational force from the incline. This is similar to the terminal velocity, but it’s not wheel-velocity dependent, meaning you could skate at any wheel velocity you wanted.
By tweaking both the incline and the track speed, you could control the wheel speed and the position of the skater on the track. If there’s really no differential bearing friction, you simply accelerate the treadmill to skate faster. In reality, the computer needs to know your position (radar/transmitter) so it can tweak the incline to keep you stationary.
Like the airplane, the two forces *can* work together to keep the plane stationary at any wheel velocity.
Any reason this doesn’t work?
Even if it could work, would it be any fun? I’m thinking standing on an umoving board (relative to the walls and ceiling of the room) with no wind blowing in your face and nothing to look at but the whizzing treadmill would get kind of boring. Then again, T-Rex doesn’t seem to need much to keep himself amused, sometimes.
Interesting.
Well I admit I was a ‘no-fly’ until I read the post, because of lack of air speed. I did not factor in that airplane wheels are meaningless in moving the plane.
It won’t end the internet debate though, too many people believe they know more than they know; they all believe they are Srinivasa Ramanujan.