What do you mean by "negate the forward motion"?
If your going to strap it down, then it won't go anywhere.
Long rod question
- Thread starter moon man
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What do you mean by "negate the forward motion"?
If your going to strap it down, then it won't go anywhere.
Are you imagining a free moving treadmill or a powered one?
The hypothetical treadmill in this situation is able to adjust it's speed to precisely the same speed in the opposite direction to which the plane would in a normal situation move forward.
Soldato
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We;re talking about a powered one, makes no difference either way.
Can I just be really annoying and throw this conundrum in 
. A HELICOPTER on a horizontal platform spinning the heli in the opposite direction and at matched RPM of it's blades. Will it take off?
(please, I hope everyone has figured out the answer after the plane one, but you never know!)
. A HELICOPTER on a horizontal platform spinning the heli in the opposite direction and at matched RPM of it's blades. Will it take off? (please, I hope everyone has figured out the answer after the plane one, but you never know!)
Can I just be really annoying and throw this conundrum in
(please, I hope everyone has figured out the answer after the plane one, but you never know!)
nothing like the plane one tbh.
Exactly.
In the same way as when a potential difference is applied across a wire, all the electrons in the wire begin to move at the same time.
Can I just be really annoying and throw this conundrum in
(please, I hope everyone has figured out the answer after the plane one, but you never know!)
Theoretically yes, because it would still create a vacuum from above. But the chopper would have broken apart long before.
That doesn't matter, unless the wheels are locked. As the wheels are free to spin on their axles, they'll just spin as much as they need to.
You're arguing about having the treadmill move backwards fast enough to slow the plane, which is contingent on the friction between the wheels and the treadmill BUT this overlooks the near-as-damn-it non-existent friction between the wheels and the axles.
Well, similar in that the fact the heli's body is spinning is irrelevant to it's take-off. Oops, there goes the answer...
Right forget the plane - think about a car on a very large treadmill the size of a runway. The treadmill is turned off. The car starts moving and accelerates to 40 miles per hour.
Then we turn on the treadmill so that it's surface is moving in the opposite direction to the cars direction. Then we ramp up the treadmill's speed and as we do so the car's tyres in relation to the road surface doesn't change and the car is still doing 40 mph wrt the road surface, however the road is going backwards at 40 mph relative to the surrounding landscape (and airmass around it) so the car's speed relative to the surrounding landscape is zero.
Then we turn on the treadmill so that it's surface is moving in the opposite direction to the cars direction. Then we ramp up the treadmill's speed and as we do so the car's tyres in relation to the road surface doesn't change and the car is still doing 40 mph wrt the road surface, however the road is going backwards at 40 mph relative to the surrounding landscape (and airmass around it) so the car's speed relative to the surrounding landscape is zero.
Soldato
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Can I just be really annoying and throw this conundrum in
Will it take off?
No.
Because the pilot would be too busy vomiting everywhere.
Soldato
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You've forgot that planes don't generate their motion through their wheels.
No, you've missed the point - its about relative speed of plane to treadmill surface and treadmill surface to surrounding environment NOT effect of treadmill on the tyres of the vehice.
Can I just be really annoying and throw this conundrum in
(please, I hope everyone has figured out the answer after the plane one, but you never know!)
Assuming the air has negligible viscosity (which it does, mercifully) and doesn't "adhere" in some way to the platform, then the helicopter will take off.
How does that affect the scenario? I don't see it matters how the car or plane gets up to speed.
Why does this make a difference?
It honestly feels like you're all in on a joke to make me look silly. I struggle to believe that so many of you believe the plane would take off. It beggars belief really!
Correct.
Now what if we attach a jet engine to the car, so that it can generate force relative to the air behind it, rather than to the treadmill underneath it? You've just said that the car is stationary relative to the air around it, so surely introducing another force to the car/air frame of reference will drive it forwards, unless you can somehow balance the force of the jet.
