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SteveDallas · 12-07-2006, 12:30 PM

After thinking for a bit, it seems pretty clear to me that the plane will not move forward, and hence will not take off. I have written a cogent, well-argued, absolutely devastating post to explain to all you fucking idiots who think the plane will take off, that it will not.

As is my habit, I then reread the post and went about editing it to make it more organized, introduce additional supporting points, and just generally kick rhetorical ass. (Anybody who thinks my posts are incoherent should see my first drafts.)

In the process of doing so, I became convinced that the plane would indeed take off.

It's all about the wheels. What forces are at play here? We've got the engine pushing forward. We have the treadmill furiously spinning backward. Since this is physics word problem land, we don't have to worry about friction, and we're ignoring considerations of the plane changing speeds. It's true that the engines are pushing against the air, not the ground--but they're also pushing against the plane. The treadmill is also exerting a considerable force of identical magnitude in the opposite direction. However, this force has no purchase on the body of the plane. Because the wheels are spinning freely, none of the reverse force from the treadmill is applied to the plane.

I think we can all agree that we'd like to see it tried, preferably with a 747 or a Concorde.

12-07-2006, 12:30 PM	#13
SteveDallas Your Bartender Join Date: Jan 2002 Location: Philly Burbs, PA Posts: 7,651	After thinking for a bit, it seems pretty clear to me that the plane will not move forward, and hence will not take off. I have written a cogent, well-argued, absolutely devastating post to explain to all you fucking idiots who think the plane will take off, that it will not. As is my habit, I then reread the post and went about editing it to make it more organized, introduce additional supporting points, and just generally kick rhetorical ass. (Anybody who thinks my posts are incoherent should see my first drafts.) In the process of doing so, I became convinced that the plane would indeed take off. It's all about the wheels. What forces are at play here? We've got the engine pushing forward. We have the treadmill furiously spinning backward. Since this is physics word problem land, we don't have to worry about friction, and we're ignoring considerations of the plane changing speeds. It's true that the engines are pushing against the air, not the ground--but they're also pushing against the plane. The treadmill is also exerting a considerable force of identical magnitude in the opposite direction. However, this force has no purchase on the body of the plane. Because the wheels are spinning freely, none of the reverse force from the treadmill is applied to the plane. I think we can all agree that we'd like to see it tried, preferably with a 747 or a Concorde. Last edited by SteveDallas; 12-07-2006 at 12:34 PM.