Can a Plane on a Treadmill Take Off?

In article ,
says...

"muff528" wrote in message
news:OW2Ff.179$DV2.5@trnddc07...

.....OR relative to each other? If so, there could be just enough thrust
applied to overcome frictional
forces and the airplane doesn't move relative to the world so airspeed is
0.

That would have to be either a very underpowered airplane, or wheels with a
lot of friction.

BUT WAIT!!! .... ANY two objects can be said to be moving (or not) at
equal
speeds relative to each other. A point
on the conveyer belt moving east at 4mph and a jet moving west at 600mph
each have a relative velocity of 604

But there's the trick. A treadmill belt isn't really moving at all, it's
turning.
Try this for a brain scrambler. Think about a tire on your car, driving down
the highway. At the point where the tire contacts the ground, it's speed is
zero. 180° away, at the top, it is moving forward at twice the speed of the
car.

Negative - yer forgetting centripetal force.

http://www.wordiq.com/definition/Centripetal

--
Duncan

"Dave Doe" wrote in message
. nz...
In article ,
says...
At the point where the tire contacts the ground, it's speed is
zero. 180° away, at the top, it is moving forward at twice the speed of
the
car.

Negative - yer forgetting centripetal force.

? Negative what? Talking about a point on the surface of the tire, not the
wheel as a whole. Centripital force has nothing to do with the forward
velocity of that point (how it travels in one axis).

http://www.wordiq.com/definition/Centripetal

--
Duncan

In article ,
says...

"Dave Doe" wrote in message
. nz...
In article ,
says...
At the point where the tire contacts the ground, it's speed is
zero. 180° away, at the top, it is moving forward at twice the speed of
the
car.

Negative - yer forgetting centripetal force.

? Negative what? Talking about a point on the surface of the tire, not the
wheel as a whole. Centripital force has nothing to do with the forward
velocity of that point (how it travels in one axis).

Are you talking about a round tire or not - are you then talking about a
big long flat tire of say infinite length. Sorry bud, can't make the
initial assumption that's been made - as it's on a tire, and yep, even
that point, at that time - has the centripetal force.

--
Duncan

"Dave Doe" wrote in message
. nz...
In article ,
says...

"Dave Doe" wrote in message
. nz...
In article ,
says...
At the point where the tire contacts the ground, it's speed is
zero. 180° away, at the top, it is moving forward at twice the speed
of
the
car.

Negative - yer forgetting centripetal force.

? Negative what? Talking about a point on the surface of the tire, not
the
wheel as a whole. Centripital force has nothing to do with the forward
velocity of that point (how it travels in one axis).

Are you talking about a round tire or not
What other kind of tire is there?
.. Sorry bud, can't make the
initial assumption that's been made -
I'm not your bud,. And what assumption are you talking about?
as it's on a tire, and yep, even
that point, at that time - has the centripetal force.

We aren't talking about the forces at work on the wheel or tire, we are
talking about the forward velocity. I can see this concept is lost on you.

--
Duncan

In article ,
says...

"Dave Doe" wrote in message
. nz...
In article ,
says...

"Dave Doe" wrote in message
. nz...
In article ,
says...
At the point where the tire contacts the ground, it's speed is
zero. 180° away, at the top, it is moving forward at twice the speed
of
the
car.

Negative - yer forgetting centripetal force.

? Negative what? Talking about a point on the surface of the tire, not
the
wheel as a whole. Centripital force has nothing to do with the forward
velocity of that point (how it travels in one axis).

Are you talking about a round tire or not
What other kind of tire is there?
. Sorry bud, can't make the
initial assumption that's been made -
I'm not your bud,. And what assumption are you talking about?
as it's on a tire, and yep, even
that point, at that time - has the centripetal force.

We aren't talking about the forces at work on the wheel or tire, we are
talking about the forward velocity. I can see this concept is lost on you.

There is no forward velocity - there *is* a change in angular momentum
though. Do you not understand that concept?

--
Duncan

Dave Doe wrote:

We aren't talking about the forces at work on the wheel or tire, we are
talking about the forward velocity. I can see this concept is lost on you.

There is no forward velocity - there *is* a change in angular momentum
though. Do you not understand that concept?

I proudly profess to not understand that a point on the top of a tire
does not move at twice the velocity of the axis of the wheel on which
that tire is mounted.
--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

I undertand that, for any one given point on a wheel, mounted on a vehicle,
traveling horizontally, more or less, there is a forward velocity (not
constant) for exactly one half the time, and a rearward velocity (not
constant) for exactly half the time, in relation the wheels' point of
rotation. The average of this constantly changing velocity just happens to
be the same as the forward speed of the vehicle.

There is no forward velocity - there *is* a change in angular momentum
though. Do you not understand that concept?

--
Duncan

Dave Doe wrote:


Try this for a brain scrambler. Think about a tire on your car, driving down
the highway. At the point where the tire contacts the ground, it's speed is
zero. 180° away, at the top, it is moving forward at twice the speed of the
car.

Negative - yer forgetting centripetal force.

http://www.wordiq.com/definition/Centripetal

Well, I'm impressed that you know of the existence of centripetal
force. But in what possible way do you think it negates the comment
about the speeds (relative to the ground) of points at the top and
bottom of the tire on a moving car?
--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.