The question states that the treadmill runs the same as the PLANES speed, not the wheel speed. They are two different things. The statement that the wheels were free-wheeling was not an accident.Originally Posted by Killer
The question states that the treadmill runs the same as the PLANES speed, not the wheel speed. They are two different things. The statement that the wheels were free-wheeling was not an accident.
Think of it with respect to a wheelchair on the treadmill.
You're sitting in a wheelchair on a treadmill. The wheelchair wheels are free-spinning, meaning they turn w/o friction.
I stand behind you in the chair and place my arm behind the chair and hold you in place.
You power on the treadmill, and the treadmill starts to move backwards. But I just hold you there w/ my arm extended, and only the wheels spin.
The treadmill moves faster. I don't have to hold you with any more force than I am already exerting* --> the wheels just continue to spin faster and faster. Work is done by the treadmill on the wheels, but there is no force increase whatsoever on the wheelchair to my arm since the wheels are absorbing all* of the energy. The ONLY function of the mill gaining RPMs is spinning the wheels faster.
Now say I walk alongside the treadmill and push you along forward (me pushing you = thrust from the airplanes engines). The speed you move forward is completely independent of the speed with which the treadmill turns. The speed you move forward is only relational to how hard I push you (how much thrust the engines exert). If I push slow, you roll forward slow. If I push you fast, you move forward fast --> no matter HOW fast the treadmill turns.
This is basically the same thing that's happening to the plane, because the engines are pushing you relative to the air, not the ground!!
* (actually I do have to apply a SLIGHTLY greater effort to keep you motionless b/c we currently do not have ANY wheel bearings that are 100% efficient, nor is the transfer or motion from the treadmill to the wheels 100% efficient, but you get the idea). THE PLANE WILL ACCELERATE AND FLY ONCE YOU START THE ENGINES, w/ the only difference being the tires are rotating exponentially faster.
"I'm not a gynecologist... but I'll take a look."
This is what I find hilarious about this problem: The question states that the treadmill matches the plane's speed, not the wheels' speed. So, all you people that said no, if the plane never moves (as the "no" people said) the treadmill would never move either.
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Can you make your cars speed differ from the tires? Kool trick - show me how.
"I'm not a gynecologist... but I'll take a look."
Here's how it's done:
1. Attach rocket to back of car.
2. Place car on treadmill.
3. Put car in neutral.
4. Put treadmill at 20mph.
5. Ignite rocket.
Solution: Car will move X mph (X being the speed at which it is propelled by the rocket) but the wheels will rotate at (X + 20) mph.
LOL, now your car is a jet without wings
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Last 30 seconds of the clip will explain all.
http://carscoop.blogspot.com/2006/08...760888720.html
Bingo on the bolded part.
AIM: RuinerTT
2005 Nissan Pathfinder LE
But wait a minute... the first video does not prove anything...
He sets the treadmill at speed 10, correct?
He then 'gasses up' the plane to take off, correct?
However, in the original question, proposal, the treadmill is able to match the speed of the wheels or whatever, correct? *speed of the plane (Edit)
But it is biased, cuase he is gassing up the plane, but the speed of the treadmill remains at 10.
A true experiment would have him increasing the speed of the treadmill, incremental to the speed of the plane/ gas of the plane. After all, the treadmill is magically able to match the speed of the plane instantaneously.
Example, if he is creating 20 thrust to roll the plane at the ground speed of 10, and the treadmill speed is at 10, then the plane will remain stationary
If he 'gasses the plane to the thrust of 40 to roll the wheels at 20, then the treadmill should 'match' the wheels at 20, and will remain stationary again...
if he puts 200 thrust to roll the wheels at groundspeed 100, then put the treadmill at 100, the plane will remain still......
of course if his thrust makes the wheels groundspeed faster than the treadmill it will take off..... but the original question has the treadmill always matching the speed of the plane....no matter how much thrust he puts.. the wheels keep spinning as fast as the treadmill goes backwards.... * actually twice as fast (edit)
The example of the luggage on the conveyor belt:
Yes, indeed, if you put your luggage on the conveyor beltand keep walking, your luggage does not stay stationary, why? because your pull in your arm creates a force greater than the backwards motion of the conveyor belt
now try this out... try to pull a 50lb luggage by your pinky in the hallway... pretty easy huh?? now imagine putting it on a treadmill.... set the speed at 2.0... pretty easy huh? now set the speed at 10.0... what would need to happen for you to move the 50lb luggage forward? exactly.. you have to pull with much force with your arm/ pinky to keep it stationary.. let alone pull it forward. I bet if you put the speed at 20, the luggage will fly off your pinky......
Last edited by ISAtlanta300; 08-15-2007 at 05:01 PM.
I got free clear tails with my ride.....
The wheels are free rolling, until they speed up and overheat causing the bearings to fuse to the wheel the resistance will not change. 5mph, 10mph, 100mph....it would always take the same amount of force to pull the luggage whether it's on the ground or on the conveyor, no matter what the speed is.
no, it would take the same amount of force to keep it stationary, but it won't move it forward untill you pull harder with your arm. But to pull it harder you should also match the force of the pull / your arm with the treadmill speed, according to the question......
I got free clear tails with my ride.....
They are FREE SPINNING wheels, it will be no differant pulling 50lbs of luggage on a regular sidewalk as it would be backwards on a conveyor belt with you walking next to it*. ZERO differance and ZERO more effort. The conveyor can be going 10x the speed you a walking and it still won't have any effect on you pulling the luggage, it will only make the wheels spin faster.
*walking beside the conveyor belt, not on it.
Actually I am sure everyone has done the "walk backwards on a conveyorbelt" play as a kid, or even as adults (i am still tempted sometimes.. LOL), or on the escalator.... where you would walk backwards and remain stationary..... at that point you are matching the speed of the conveyor belt.
in order to get off the thing you would have to increase your pace. however, if when you increase your pace, they increased the speed, you would still be in the same place. You'd always have to overcome the speed of the conveyor to move forward.
If you put a jetpack on your back, yes you will get off... you would just have sore legs, as the pack will force you to move your legs faster and run.... but you just overcame the speed of the conveyor belt.
But if the conveyor belt matches the trust of your jetpack, your legs would prob. be burned to a cinder like fred flintstone, as the conveyor would be moving at .... oh maybe Mach 1 to match up with the speed of the rocket on your back, (with your legs burning up at Mach2 to try and keep up) but you still won't be going anywhere.....
I got free clear tails with my ride.....
Dude read the original example on this again, it clearly states "walks beside the moving sidewalk/conveyor" while pulling the lugguge on it. You aren't on it, you're not walking on it, you're walking beside it. Your arm as it pulls the lugguge is just like the trust of an engine on an airplane...
Read it again...
Let's use this analogy. Instead of looking at the airplane, let's back
up and go into the airport. Suppose you're walking down to your gate
and pulling your carry-on bag behind you. It's a nice new bag with low
friction wheels. No problem! Up ahead you see one of those moving
walkways. You don't see anyone coming, so you decide to do a little
experiment. You go over to the walkway that is moving TOWARDS you and
place your bag on it. Meanwhile, you step off to the side of the
walkway, and still holding on to the handle of your bag, you continue
to walk along. In fact, you intentionally walk along at the same speed
that the moving walkway is going, just in the opposite direction.
Question: does the bag move or does it remain stationary as you keep
walking? Obviously it moves with you. So why does your bag move
forward when you are walking at the same speed of the conveyor going
in the opposite direction?
The answer to that question is also the answer to the
airplane-conveyor question. To complete the analogy, the pull of your
arm is analogous to the force of the airplane engines. The bag's
wheels are analogous to the airplane tires. Do the nice low-friction
wheels on your bag on the conveyor pull against you anymore than they
do when you're just pulling your bag along normally? No, they don't.
They are free-wheeling, after all. Meanwhile, you're pulling the bag
with the same force in both cases. So in both cases, the bag keeps
moving forward. Likewise with the airplane, the pull of the engines
doesn't change nor does the force on the airplane imparted by the
tires change no matter what the ground is doing underneath the tires.
You have the same force imbalance in either case, and since Force =
mass x accceleration, you have the same acceleration. Remember, we are
talking airplane engines which push against the AIR, not the ground.
The acceleration is with respect to the AIR, thus the airplane
develops a speed relative to the air and can eventually take off...
John Strong
Ph.D., biochemical engineering
M.S., chemical engineering
B.S., mechanical engineering
OMFG YOU PEOPLE ARE FUCKING RETARDED...... THE PLANE WILL TAKE OFF.... THE ANSWER IS YES....PLAIN AND SIMPLE....
THE WHEELS DO NOT MOVE THE AIRPLANE THE ENGINES THRUSTING AIR DO.....IF THE TREADMILL IS SET AT 100MPH AND THE AIRPLANE IS MOVING FORWARD AT 100MPH THE WHEELS WILL BE ROTATING AT 200MPH...THE TREADMILL AND THE AIRPLANE ARE MOVING AT THE SAME SPEED IN OPPOSITE DIRECTIONS....
FUCK.. BUNCH OF FUKING IDIOTS
lol, hektik's gonna kill someone
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The speed of the plane, even without the treadmill, would be less than 10mph. Knowing that, it shows that even though the treadmill is going faster than the plane can forward (w/o the treadmill), the plane STILL moves forward.
AIM: RuinerTT
2005 Nissan Pathfinder LE
..
ISAtlanta300 - I see that you are about 35. Come on, man, use your head. Have you had any advanced college courses on Physics? Hell, ANY physics courses? You obviously cannot grasp this simple concept.
I'm being serious. The plane WILL take off. We can set up a wager and put the money in escrow until there is more proof if you would like. How does, $50,000 sound? THAT is how confident I am that the plane will move forward and take off. Are you that confident as well?
By the way, walking on an escalator is not a true analogy. Your feet/legs are what move you and they have to use the ground to push forward and create that movement. A plane, however, uses the AIR to push forward, not the ground. There is no speedometer to the wheels and there is no powertrain to the wheels. The wheels are ONLY there to hold the plane off of the ground. Because they spin freely, they provide no effect on the plane.
AIM: RuinerTT
2005 Nissan Pathfinder LE
The fact this thread has gone on for more than a year when the answer was given on the first page makes me sad.
Doesn't it, though?
AIM: RuinerTT
2005 Nissan Pathfinder LE
So you're saying that, before he "gasses it," that he has the throttle on the plane matching exactly speed X (in this case 10)?
What is clearly shown is a plane tied to the treadmill (no throttle). The instant the kid adds throttle (meaning the plane has not had time to accelerate to "speed 10") the plane begins to move forward.
Oh, and along with Ruiner, I will also throw in $50,000.
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I haven't had any college physics courses, I must be dumb!!
Hush, you are just naturally gifted.I haven't had any college physics courses, I must be dumb!!
AIM: RuinerTT
2005 Nissan Pathfinder LE
Who da fuck cares what the wheels are doing.. are you saying that if i fly at 100 mph and suddenly encounter a hurricane headwind at 100mph hurricane level I would just fly through it and not stall out?
I got free clear tails with my ride.....
Hey just want to keep adding (jet) fuel to the fire.... Devil's advocate.. lol
I got free clear tails with my ride.....
this whole time i was mis-reading the statement
now that i re-read it, it seems to be so simple. But correct me if im wrong.
in lamens terms, the plane needs to go speed A to take off. If the treadmill is going speed B in the opposite direction, then the plane will need to go speed c, which is B speed plus whatever speed is needed to match A speed. Remember that B speed, because it is moving opposite, will be a negative variable.
A: plane speed
B: treadmill speed
C: speed needed for takeoff
X: Variable speed needed to make A
C: (B+x=A)
now im trying to figure out why there is a debate, because the highest science class ive taken is high school chemistry, and after i understood the question, the answer came naturally.
it helps to put fake numbers. Lets say 300 knots is needed for a plane to take off, Well the treadmill is running at -300 knots because it is going backwards, therefore, the plane would essentially need to put out 600 knots of power in order to reach 300 knots in forward speed. I think I've got it simplified enough.
Who da fuck cares what the wheels are doing.. are you saying that if i fly at 100 mph and suddenly encounter a hurricane headwind at 100mph hurricane level I would just fly through it and not stall out?
OMG are you kidding me.....this is a treadmill
it does not produce headwinds.... you simply place the objects wheels on top of the belt. (the black peice for your third grade ass... ) and the airlpane rolls on top of it ...what does 100mph headwinds have to do with the original equation....
you simply place the airplane on top of the treadmill like this
now imagine the treadmill is just as long as a regular runway at hartsfield airport.the wheels are free rolling (which means they DO NOT POWER ANYTHING. they just roll.) so no matter how fast the treadmill is going the airplane will still move forward. the wheels will just move at the speed the airplane is going PLUS the speed the treadmill is going .. this has nothing to do with headwinds, incline, rotation of the earth, wether or not the fat bitch in row 3 farted earlier, or if a butterfly flapped its wings in july....STOP THINKING SO HARD INTO THE QUESTION....
Who da fuck cares what the wheels are doing.. are you saying that if i fly at 100 mph and suddenly encounter a hurricane headwind at 100mph hurricane level I would just fly through it and not stall out?
OH AND THANKS FOR PROVING MY POINT... YOU GUYS ARE A BUNCH OF IDIOTS...
negative, the plane needs NO additional power to reach any speed. The conveyor has ZERO effect on the speed or power of the plane, it will only make the wheels spin faster.
Fuckin tards - lol. WE HAVE LIFTOFF!
"I'm not a gynecologist... but I'll take a look."
FUCK
WHAT DO YOU MOTHER FUCKERS NOT UNDERSTAND ABOUT THIS.
THE ONLY THING THE FUCKING WHEELS DO IS HOLD THE PLANE OFF THE FUCKING GROUND. IT DOESN'T MATTER HOW FAST THE WHEELS ARE MOVING OR IF THE TREADMILL MATCHES THE SPEED OF THE WHEELS. THE PLANE DOES NOT USE THE WHEELS TO PROPEL ITSELF.
FUCK YOU PEOPLE ARE RETARDED
Wrong. No matter what speed "B" is, it will not make ANY difference in how the plane functions/takes off. All that speed "B" will do is spin the wheels (that spin freely) on the plane more quickly. Spinning the wheels will not stop it from going forward, however.
AIM: RuinerTT
2005 Nissan Pathfinder LE
No, you still don't understand it.
Do this:
Take a matchbox car and a piece of paper out. Now, put the matchbox car on the piece of paper and push it foward. After you push it forward, "pull" the paper back very quickly. The paper = the treadmill.
Does the car KEEP moving forward even though you pulled the paper back as fast as, if not faster, than the car was initially moving forward? The answer is yes. THERE is your answer. The car continued to move forward, but the WHEELS on the car just spun faster. It didn't change the forward momentum, though.
AIM: RuinerTT
2005 Nissan Pathfinder LE
If you don't understand this:
or if you do not understand this:Do this:
Take a matchbox car and a piece of paper out. Now, put the matchbox car on the piece of paper and push it foward. After you push it forward, "pull" the paper back very quickly. The paper = the treadmill.
Does the car KEEP moving forward even though you pulled the paper back as fast as, if not faster, than the car was initially moving forward? The answer is yes. THERE is your answer. The car continued to move forward, but the WHEELS on the car just spun faster. It didn't change the forward momentum, though.
Then stay off the drugs.
"I'm not a gynecologist... but I'll take a look."
So you're saying a treadmill creates headwind? What kind of treadmills do you use?Who da fuck cares what the wheels are doing.. are you saying that if i fly at 100 mph and suddenly encounter a hurricane headwind at 100mph hurricane level I would just fly through it and not stall out?
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It appears I will have to take matters into my own hands. The plane takes off, get over it. I am locking this thread.
I am locking it too.
"I'm not a gynecologist... but I'll take a look."
Me too
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Dayummm triple locked. Nobody's gonna post in this biatch now.
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