Can Plane Take Off

It will take off if there is a cat taped upside down to the bottom of it.

If the plane is capable of generating 1G+ of thrust from its engine, it could conceivably take off on engine lift alone, regardless of wing lift. Say the Harrier jet, for instance. Or an F15 on afterburners pointing straight up.

I never saw this thread in the "olden days". Upon reading it today, for whatever reason my mind"s eye visualized something like a Wright Flyer--the notable thing being that such airplanes had skids, not wheels, with minimal power. That kite ain"t going anywhere Of course, give a rickety box like that enough headwind and it could fly with zero ground speed or even look like it"s flying backwards. I suppose that"s just due to my natural tendency to look for exceptions to the rules. Now an hour later I find myself at the opposite end of the tech curve, wondering whether a fully-loaded Concorde"s landing gear would fail before it reached stall speed.

My old man spent most of August and September 1945 on a Navy troopship moored in Tokyo Bay not far from a small aircraft carrier. Given the lack of options aboard ship, he said his favorite form of entertainment was to watch the planes taking off from the CV go into the drink with surprising frequency.

Danth

Propellers and jet engines apply to physics the same.

hay guys

Wright State University is closed today Feb 12, 2008, due toincrementweather. All classes are cancelled, and all university offices and libraries are closed. Faculty and staff should not report to work. Please check the university web homepage or the university info phone line at 937 775 3500 for updates to this message.

Stay warm and safe.

This mailing list is maintained by the WSU Office of Communications and Marketing and is used ONLY for official university announcements.

Click to expand...

lendarios said:

Just look at seaplanes. They dont have wheels, they just slide based on the Air movement generated by the engine. It is the same principle. Movement is generated from the engines, not from the friction.
they are generating forward motion in a frictionless surface such as water.

Click to expand...

Water is frictionless, huh?


It"s a pretty simple problem. Airplanes move in the air, not on the ground. It"s a freerolling wheel, its just going to go faster in the opposite direction and not impede the plane"s forward movement caused by its propulsion system: jet or propellor.

If you removed the wheel and lay the plane down on the belt, and then matched the conveyor speed with the forward speed of the plane accounting for friction, yeah no shit it would stay in the same spot as there"d be no forward movement.

Bottomline is that even if you fuck with the semantics, there is no way to make the conveyor belt move enough to hinder the plane"s forward movement.

Setting up the question: "IF YOU CAN GET A TREADMILL TO HINDER ..." is the trick part of the question. You can"t do it. IF you could, yes, the plane would stay still. You can talk about a powered treadmill to match it (good luck!), you can talk about the plane"s forward movement engaging a treadmill that matches the velocity inversely, whatever.

It"s identical to the question "If you get a rooster to lay an egg, what are the odds the new chick is a hen?" Do you ignore the if as it is impossible for a rooster to lay the egg, or do you embrace the if and give the correct answer?

Who gives a shit. Bottomline is I wish mythbusters would have gunned the tarp and driven like 5x faster to show that the velocity of the treadmill has absolutely no bearing on the forward motion of the plane.

I have come to the conclusion that I am indeed retarded for not just drawing a force diagram and being done with it.

/hangs head in shame

It"s a little over thought, and sorry btw for bringing up old shit, but zomgz the FREE BODY PHYSIX DIAGRAMS!!!1

I could never understand how this problem generated so much contention.

The answer is simply: Yes the plane will take off while it"s wheels are spinning twice as fast compared to a normal take off.

The fact that we have had input from thousands of college level physics students and professors from around the world debating this along side 10"s of thousands of bi-pedal logic warriors shows the dichotomy of the modern world.

We are pushing the boundaries of human achievement in both directions. It"s just interesting when parties from both movements come together to discuss something. It"s like watching pro athletes and children play on opposing teams and yet for some reason both sides are taking heavy casualties.

I think the only way this problem can have any redeeming qualities is if the airplane is a DC-8 space-plane that is transporting all operating thetan"s to mars to start a new world, away from us.

Then I think everyone can agree that the plane will take off... as all of humanity will ensure that it gets to mars one way or another.

i think the ice cube question is the new one.

an ice cube is in a glass of water. it melts.

will the water level raise, lower, stay the same?

a little more detailed explanation

The water level remains the same when the ice cube melts.

A floating object displaces an amount of water equal to its own weight. Since water expands when it freezes, one ounce of frozen water has a larger volume than one ounce of liquid water. A completely submerged ice cube weighing one ounce, for example, displaces MORE than one ounce of liquid water. The cube will rise until the volume remaining under the surface displaces only one ounce of water.

If you could remove the ice cube and leave a "hole" in the water where the cube used to float without disturbing the surrounding water, that hole would take exactly one ounce of liquid water to fill. Let the ice cube melt. Since it is now one ounce of liquid water, putting it back into the "hole" will exactly fill it and leave the remaining water undisturbed.

Answered by: Paul Walorski, Part Time Physics Instructor

Tarrant220 said:

New? I saw this on Mr. Wizard back in like 1980something.

Click to expand...

itll still be a fun topic when everyone is drunk / no one that watched mr wizard is around to spoil it.

lendarios said:

Water will not remain the same. The density of an ice cube is different from the density of liquid water. I think it will be less water since water is an unique liquid that when in solid form takes more room than in liquid form.

Click to expand...

read my post right above ^^^^^ it explains why this is not the case. this would only work if you were forcing the ice cube to be completely submerged.

Tarrant220 said:

Incorrect. It"s not about density, its about the space the water displaces, the amount of displacement the water has in cube form is the same it has in liquid form.

Click to expand...

no it isn"t. the frozen form occupies a larger volume. the "excess" frozen volume will rise above the water level. if a part of the cube is not in the water, it isnt displacing anything.