/sci/ - Science & Math

>>10462612
what the fuck is a "pidgeon"?

>>10462612
bird that weighs 0.3kg

>>10462617
yeah i spelled it wrong what you gonna do about it clownboy?

>>10462620
your question is meaningless because pidgeon is not a real word

>>10462621
the question stands the pidgeon is imaginary bird that i thought up. Get over it kid.

>>10462624
>imaginary bird
there is no way to determine from the problem that the "pidgeon" is a bird. further, if it is imaginary, the laws of physics need not apply to it and thus the problem is unanswerable.

change your diapers before reposting your nonsense problem b/c you reek of bullshit

lol this is like an even more retarded troll version of the flies in a jar. >>10450718

>>10462612
the fact that pigeon was spelled wrong gives everybody an excuse for not admitting that they cannot solve this ..

i'm no physics/sci major (just a lowly philosopher here) but i think i know a bit about the first case .. if you mentally replace the air with water, it becomes clearer that the weight should remain the same ..

but about the second im curious, i really don't know .. can anyone tell me ? thanks ..

OK, well i'll bite.

Question b) The cage with a flying bird will be just the cage weight. that's easy.

now what happens if we bring the bars closer and closer together until the bars get air tight and it effectively becomes a box. is it cage plus bird or just bird? I gonna go with still just box weight.

>>10462666
brainlet

>>10462671
enlighten us with your smart answer then genius.

>>10462612
Oh god i wish to be strangled by her

bird

I like birds

>>10462612
is this the end of /sci/ can really noone solve this? So much for the high IQ board.

It's clearly 2.3 kg in case a)

next

>>10462689
the answer is 2.3kg for a closed box. if the “pidgeon” is flying then it’s weight is being held up by its wings using the air as a support. (think of how a helicopter landing blows dirt on the ground—it’s transferring force to the ground. also look up “ground effect” in flying like e.g. how pelicans can fly very close to the surface of water without needing to flap much at all). so the pidgeon flying in the closed box is same thing as if it were being supported by a rod. if it were a cage or an open box, though, the air could transfer the force to stuff not supported by the scale, so it’s not clear then, but closed box it’s deffo 2.3

>>10462774
>>10462891

>>10462612
I'm eating rn, and I'll fuck you in the ass when I come to my laptop.

The box weighs 2 kg. The box will always weigh 2 kg regardless of its contents. Also, what kind of fucking box is this?

>>10462612
A african or european pidgeon?

>>10463050
Nepalese

>>10463016
Doesn't matter. Consider just the stuff that is specified. You don't nee to know what kind of box it is to solve this. PICK THE SIMPLEST MODEL.

>>10462998
yeah i also think this but idk.

>>10463091
I solved the problem. The box weighs 2 kg. It's in the problem statement.

>>10463105
The solution is trivially easy if you draw a free body diagram

>>10463120
NO. if you put the box with the pidgeon flying inside it on the scale what will it show.

>>10463125
>I've seen smart people use the word trivial
There's a reason people use these words, anon. It's not too brag how trivially easy things are from your mastermind perspective. It's because it can guide the reader to know where the hard parts in a proof or something are.

>>10463133
This is why I need to know what kind of box it is. I'll assume it is corrugated cardboard. 2 kg is pretty decent size box if it's cardboard, which gives the bird room to fly parallel to the weighing surface. It will generate some thrust. The problem has no solution with the given information.

>>10462612
The cage "weighs" as much as it always did, 3kg.

The problem isn't asking what a scale would read if the pigeon-cage system were sitting atop it, it's simply asking what the cage weighs. Since the weight is presented as a Mass, it's fair to assume the question is really about the mass, which doesn't change.

>>10463325
i guess i have to remake it because you assclowns will run around the actual question and not answer.

>>10463449
The actual question is what is the weight of the box

>>10462612
This require experimentation. Does anyone have a large enough box and a pigeon nearby? If so, can you run the experiment?

I would guess the confusion would be between the mass/weight confusion. So it's really a problem about the forces of applied to the scale. So we have the boxe's own weight, the mass of the air can be ignored if we assume it of the same pressure as the room and the force equal to the lift of the bird, which if it is constant should be the Weight of the bird. Now for the closed cage there should be complicated vorticitied going to the sides but it doesn't matter. That just means the bird has to work harder to stay afloat. So the scale will still in all cases read 2.3 kg. Thing is flaps of wings are not constant so it will waver between 2~2.3

>>10463578
Wrong. The bird is flying parallel to the weighing surface with some velocity because it's in a giant ass box. This provides lift due to pressure differential.

>>10462612
The pigeon needs to match the Earth's pull by exerting the same force except upward. Assuming that the box is airtight, the weight would fluctuate as the bird's wings flap. If the pigeon was instead something that flies evenly like an RC helicopter, the weight would be very close to 2.3kg
For the cage, it would measure very close to 2kg because the force of the air is directed outward and not recycled, the net effect being that the pigeon could be anywhere else and affect the cage's apparent weight just as much.

>>10462612
Assuming the box is completely air-tight, and that force cannot be exerted through the sides of the box, wouldn't it just be 2.3kg because all the weight of the pigeon would still be carried through the box?
Also, the box would still weigh 2kg because the question doesn't say that it has to be the combined weight of the two
The cage would be 2kg because pressure would be able to escape through the spaces inbetween the bars.
The cage would still weigh 2kg btw because the bird wouldn't change the actual weight of it.

who made the stins,gate art

>>10462612
the cage will weigh 2kg, if the box is closed then it will weigh 2.3kg

>>10463125
>trivially easy
>hey I'm smart btw

>>10462621
>>10462630
Absolutely S E E T H I N G

>>10462998
Except that the air supporting the bird converts to equal pressure on all parts of the box, up and down included, wich nullifies the bird's weight while flying. So it's 2 Kg.

Also the box's weight is the same either the bird is resting on it or not.

>>10464435
this nigs right

>>10462998
imagine being this fucking retarded

>>10467778
he's right y'know

>>10462612
>>10464435
The box will be 2.3kg

For the lattice It really depends on where you put the scale, if the cage has a lattice or solid bottom and what the air space of the lattice is.

With a compression scale or a solid bottom of sufficient will show a little less than 2.3 kg up to exactly 2.3 kg depending on how much area they cover. With a lattice bottom and a hanging scale the scale will read a little more than 2.0 kg if you reduce the air space of the lattice the scale will read more and more until it reaches the same as the box where the total area is what matters.

A bird is kept aloft by accelerating air downward and this air pushes on things below it in equal measure to the bird's weight distributed as pressure. The higher up the bird is the more area this weight is spread over.

This was taken directly from reddit. I know... because I go there frequently.

Since it's not specified, let's assume the box is as big as a football field. Let's assume the temperature is not the same in every place and this leads to ascensional current. The pigeon rides them passively to fly. What's the weight?

>>10467792
2.3kg

>>10467798
At a certain point the pigeon gets a stroke, and starts free fall. What's the weight?

>>10467798
Let's consider the universe as an infinite closed box (3D set) we should feel the weight of all the satellites above us.

>>10467802
OH FUCKING I FEEL IT IM CRUISjING

>>10467800
>and starts free fall
2.0kg
>reaches terminal velocity
2.3kg

>>10467802
Only insofar as that the satellites have mass and therefore a gravitational pull that attracts us.

>>10467812
>Only insofar as that the satellites have mass and therefore a gravitational pull that attracts us.
So does the bird with the eart, and thus, it's the same case.

>>10467825
Satellites aren't kept aloft by exerting force on the atmosphere. Also their pull is so small that it can be considered negligible. As would the gravitational pull of a bird on the scale.

>>10462612
2kg in both instances. The weight of the box is requested, not the weight of the system.

>>10467834
ohhh op btfo

>>10467834
you're a faggot and nobody likes you

>>10467844
i like him, your argument is invalid

>>10462998
Brainlet answer. The question says the box weighs 2 kg and proceeds to ask how much the box weighs. Obviously the box has mass of 2 kg. The system itself weighs 2.3 kg but that's not the question.

>>10467858
you like him? means you're a faggot aswell

>>10467883
Weight is not mass. Asking what something weighs is to ask what it will be measured as on a scale, not anything else.

>>10467910
Then the question is underspecified to calculate the forces involved in flight.

>>10462624
I like your moxy, sister.

>>10462612
2.3 kg for box assuming it's closed and 2 kg for cage assuming it's open

>>10462939
/sci/ is notorious for being a low IQ board though.

>>10462612
2.3 kg in both cases. But not because of all the brainlet answers. It's because flight is impossible in a closed system.

>>10468627
*meant to say 2kg cage. but 2.3 box.

You guys are all fucking idiots. Its a closed system containing 2.3 kg of matter. If you think it weighs 2 kg because the bird is flying you're an idiot.

The specifics are difficult. If the bird is sitting on the floor and does a power squat the box might weigh more. And when it slams into the roof it might momentarily weigh less. The fluid flow of flapping wings is outside the bounds of whats reasonable for a thought experiment. The important part is that its 2.3 kg on average.

When its a cage its not closed system anymore. The question isnt answerable. It could be more than 2kg if the thrust of the bird pushes on the wires of the cage. It could be negative if the bird flies off wearing the cage as a hat. The problem isnt defined.

There. there's the only answer this stupid fucking question deserves.

>>10468639
Imagine be so fucking dumb you think it weighs 2.3 kg when the bird is flying.

>>10462612
The question is wrong.

Weight is a force but here stated in kg which is for mass.

The mass of the box remains unchanged no matter what is inside.

>>10469623
Number on scale of box remains unchanged if something was put to magnetic levitation inside?

https://youtu.be/N0IGrSjcBZs
>>10464435
The cage will be somewhere between 2 and 2.3 depending on multiple factors, including but not limited to its dimensions and how high the pidgeon is

Bump because those fucking retards can't play some Pusey

box is 2.3
cage is a tad over 2

>>10463578
Well, (correct me if I'm wrong, am currently only in highschool physics) wouldn't the weight remain constant? Weight is just how much gravity affects the mass of the box and its contents, which isn't changing. The scale only measures the normal force, which I guess would waver, idrk.

>>10467751
No it doesn't. In dynamic situations, air pressure is different in different directions. Were that not so, flight would be impossible.

>>10462612
>X weighs Y kg

>>10462612

>>10469623
Although in SI units force is measured in newtons, one earlier measurement system did measure force in kilograms. Though doing so is discouraged now, it doesn't automatically make the question wrong.

>>10469676
That would depend on where the other magnet (or repelling superconductor) was.
In any case, the scale measures weight (force) not mass, and then converts the measurement to the mass that would produce that force.

>>10467751
But that's false

>>10468639
You are so incredibly stupid, it's simply unfathomable.

Weight is the measured by the net force of gravity and other forces. If the bird is stationary, sitting on the box, the entire thing will weigh 2.3 kg. When it is flying however, the force produced by the bird won't be anisotropically downwards. Therefore it would not weight 2.3 kg.

>>10472000
Then the problem is too hard, since we would need to know the sizes of the box and the bird, as well as the bird's position of the bird inside the box to represent a pressure gardient that could give us the weight shown in a scale.