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/sci/ - Science & Math

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7263990 No.7263990[DELETED]  [Reply] [Original]

Discuss.

>> No.7263997

Flies are adding to the air pressure and pushing air down with at least force equal to their weight.

Jar reads 1.5

>> No.7263999

depends on if the jar was on the scale before the flies have been added.

>> No.7264000

>>7263999
>past-dependent weight

>> No.7264004

>>7263990
1kg, as the flies aren't touching the jar or the scales

>> No.7264014

>>7264004
>Newtons 3rd law doesn't mean anything guize

>> No.7264028

the scale measures forces felt on it

the jar exerts a force on the scale because of gravity

the time average force of the flies in any direction is zero, because for any time spent flying any direction, they fly just as much the other way.

so just the weight of the jar

>> No.7264032

it's 1.5 kg. any other answer was given by a literal retard

>> No.7264034

>>7263990
flies constantly keep moving so it wuld fluctuate from 1kg to 1.5kg, maybe not even reach 1.5kg

>> No.7264036

>>7264014
The flies aren't pushing or pulling on the jar, otherwise it would show as 0.5kg (1.0 - 0.5)

>> No.7264037

>>7264036
>a closed system somehow weighs less than its enclosed mass
no. go back to hs

>> No.7264039

>>7264034
It would fluctuate AROUND 1.5 kg, not strictly less than.

>> No.7264041

>>7263990
>.5 kg of flies

That's a lot of flies

>> No.7264047

>>7264036
Fucking retard

>> No.7264049

1.5 kg once all the flies die

>> No.7264050

>>7264037
By your logic if 500g of flies were flying above a set of scales the scales would pick them up.
I think you need to go back to hs

>> No.7264054

>>7264050
>closed system
maybe you should go back a little further than hs it seems you are illiterate

>> No.7264063

>>7263990

1 kg. The flies produce thrust with their wings. Thrust is the change in momentum of the air in the jar caused by the fly wings. So the air moves. The amount of thrust produced by the flies is enough to support their weight, but that thrust is not transmitted to the bottom of the jar.

>> No.7264066

>>7264063
>but that thrust is not transmitted to the bottom of the jar.
Where does it go, smart guy?

>> No.7264067

>>7264066

The thrust is transmitted to the air. The air accelerates (or changes momentum, however you prefer to think of it).

>> No.7264068

Thrust or lift?

>> No.7264070

>>7264067
Go get a kitchen scale and blow on it.

>> No.7264071

i fucking hate this board

>> No.7264072

>>7264067
>it goes into the air
>it goes everywhere but the bottom.
ok

>> No.7264073

>>7264068
what do you think bitch boy (it's thrust)

>> No.7264076

>>7264070

Yes, granted, if you blow hard enough the scale would register. But in this problem we are talking about flies (very little thrust) and the OP asks for 1 kg or 1.5 kg. So strictly speaking the answer might well be 1.00001 kg but the fact of the matter is that realistically the scale will read 1 kg and nowhere near 0.5 or 1.5 kg.

>>7264072

See above. The majority of thrust will go toward accelerating the air via flow entrainment. So yes, some minute force may reach the bottom of the jar.

>> No.7264082

Fucking bernouli principle faggots, if the flies moved the air there would actuall be a lower pressure zone. Theyre not kangaroos, theyre not exerting force downward.

>> No.7264084

>>7264082

Flies flapping their wings is doing work on the air so Bernoulli's is not useful here.

>> No.7264085

>>7264082
4/10 a retard might bite but i'm not retarded so fuck off

>> No.7264094

Op here, posted this same thread on /b/ half an hour ago and somhow sci actually gave more retarded answers....I thought you guys were smart?

>> No.7264102

>>7264094
Stupid threads get stupid answers

>> No.7264112

>>7264076
but these are theoretical flies that weigh half a kg and so exert that much force on the air

>> No.7264124

>>7263990
If the jar is perfectly closed on top, the scale will display 1.5 kg.
Otherwise, it will display something fluctuating slightly above 1 kg.

>> No.7264125

The scale reads the normal force exerced by the jar upon the scale. Since it's acceleration is 0, normal force equals it's weight, so 1kg.

>> No.7264129

The jar weighs 1 kg and that is what the scale will read end of story

>> No.7264130

>>7264125
>>7264129
no.

>> No.7264147

>>7264130
Yes, now go back to /b/.

>> No.7264149

>>7264147
you're a fucking stupid idiot

>> No.7264164

>>7264036
so dumb

>> No.7264348

1 kg

>> No.7264354

>>7264036
lol

>> No.7264390

>>7263990
Think of it like this: Does air have weight? Of course it does. All gasses have weight. The pressure exerted by the atmosphere is already accounted for by the scale, but if there was some way to create a vacuum inside the jar, it would weigh less. Now put in flies. No matter where they are, or how they fly, they will always exert a downward force because they have mass and gravity exists. Because air has mass, it is effected by this force.

Imaging the jar being filled with water. If floated weights on top of the water, it would obviously add weight to the total. Water just happens to be a liquid, while air is a gas. It doesn't change anything about the mass and force due to gravity.

The combination weighs 1.5 kg.

>> No.7264394

>>7263990
Are the flies alive or dead?

>> No.7264396

It depends if the scale was zeroed out via tare before the flies were put in

>> No.7264405

When I swim in a pool, the weight of the pool + me = the initial weight of the pool.

Yup.

>> No.7264407

>>7264070
I have a double digit gram scale that easily registers differences in air pressure above it.

eat a dick nigga.

>> No.7264412 [DELETED] 

>>7264390
The OP never mentioned air. The only thing thing it tells us of are a scale, a jar, and flies, therefore we can only assume the scenario pictured here takes place in a vacuum.

>> No.7264415

>>7264412
>we can only assume the scenario pictured here takes place in a vacuum
>flies are flying
>in a vacuum
gtfo retard

>> No.7264416

>>7264390
The OP never mentioned air, the only thing thing it tells us of are a scale, a jar, and flies, therefore we can only assume the scenario pictured here takes place in a vacuum.

>> No.7264417

>>7264412
You're right, and since in the picture the flies are floating, it must be in a zero gravity situation.

Well played, OP.

>> No.7264418

>>7264416
>therefore we can only assume the scenario pictured here takes place in a vacuum
>flies are flying
>in a vacuum
once again, gtfo retard

>> No.7264419

What the fuck kind of flies weigh half a kilogram

>> No.7264420

>>7264418
op didnt say it wasnt in space

>> No.7264421

>>7264416
Then the flies are dead and at the bottom of the jar. Also, without air, they are at the bottom of the jar, since they can't fly. I think air is implied.

>> No.7264422

>>7264420
>there is no option for the scale reading 0
it's not in space, and its not in a vacuum you stupid wanting to be clever but actually just retarded sperg faggots

>> No.7264423

>>7263990
missing information, you also need to know how much the scale weights to solve this.

>> No.7264424

>>7264423
fuck off, no you dont you faggot

>> No.7264425

>>7263990
But how much does the lid weigh?

>> No.7264427

>>7264076
the thrust for 500g of flies is about 500g, genius.

>> No.7264429

>>7263990
what is the weight of the gas inside the jar?

>> No.7264430

>>7263990
how big is the jar?

what is the atmospheric pressure?

how much weight would the air add to this jar without the flies?

regardless all the choices are probably wrong

>> No.7264431

>>7263990
How much do the letters above the jar weigh?

>> No.7264438

>>7264430
Don't you mean irregardless?

>> No.7264439

>>7263990
impossible to answer, but the answer is higher than 1.5kg

if the jar weighs 1kg by itself, and the flies add .5kg, the air inside adds to that, but you need to know the volume of the jar as well as how much air is offset by adding the flies.

>> No.7264444

>>7264439
>the air inside adds to that
it's at atmospheric pressure, so no it doesnt

>> No.7264448

>>7264438
They're interchangeable words.

>> No.7264451

>>7264439
If you were to fill the jar with a gas that is more or less dense than air, sure, but otherwise, this is already calibrated by the scale. When you turn it on, the 1 atm of pressure is constant

>> No.7264454

>>7263990
how do you know the scale is accurate?

>> No.7264455

>/sci/ is so stupid they cant answer a simple question
>resort to mindless lel i troll you to cope with the fact that their retarded

>> No.7264456

Thank you for labeling the scale.

I would have been completely lost without it

>> No.7264460

>>7263990
why is there a blue portal above the jar?

where is the orange one?

does it lead to a planet with a higher gravity?

>> No.7264462

>>7263990
the scale clearly reads 111111

>> No.7264466

>>7264004

someone's never taken an elementary physics class.

>> No.7264470

.5 kg of flies is a lot.
Each one of those flies is 100 grams.

>> No.7264471

Holy shit I can't tell if these people are trolling or literally retarded

>> No.7264481

weight = 1kg + 0.5kg + J(flies in z axis)

J(flies in z axis) being the impulse of the flies in the z axis, or the force exerted over time by the flies accelerating in the z axsis.
This will average to 1.5kg over time. An instantaneous measurement will be higher or lower that 1.5kg based on the movement of the flies.

>> No.7264483

>>7264049
This man is the only sane man in this thread!

>> No.7264484

haha I always said sci was the 2nd smartest board but we are stumped by this little riddle!

>> No.7264487

>>7264484
>we
speak for yourself dumb nigger

>> No.7264489

>>7264484
what's the smartest?

>> No.7264492

>>7264489
probably /k/ or /pol/

maybe even /out/

>> No.7264498

>>7264492
Then go there

No need to shit up this board with grade school physics

>> No.7264501

>>7264489
>>7264492
That goes to /a/, there the only board smart enough to chase new comers if they are too stupid to get information on said anime. But the again I could be wrong...

>> No.7264505

/pol/ > /sci/ > /out/ > /lit/

>> No.7264506

The scale doesn't read anything because it is an inanimate object, and thus cannot read.

Did I solve it?

>> No.7264516

>>7264501
>No need to shit up this board with grade school physics

/sci/ can't even solve grade school physics problems you dolt. perhaps it should be shitted up with preschool problems since you can't even solve this simple problem

>> No.7264519

>Discuss

Holy shit that's a shitload of flies.

>> No.7264523

>>7264516
Wrong post sir

>> No.7264527

It would never reach 1.5kg but it would exceed 1kg. The pressure exerted by the flies upon the air doesn't have the same impact as the pressure they would exert upon a solid object, I feel I need not explain why a gas and solid are vastly different. The downwards pressure would expand or radiate outwards with the chain reaction caused between the air molecules, 0.5kg of force exerted by a fly half way up the jar would never translate to 0.5kg of force directly on the scale.

Anyone simply answering 1.5kg either doesn't care enough to discuss this point further or are nearly as stupid as the people who are actually underage and answering 1kg.

>> No.7264530

>>7264523
ayy lmao you're right

meant to send it to this sperg
>>7264498

>> No.7264536
File: 16 KB, 250x250, image.jpg [View same] [iqdb] [saucenao] [google]
7264536

> out of a mysterious blue portal 5 angry, heavy red flies appear.
> by bending space further, billions come breaking into the world and begin devouring the humans.
> added weight of flies causes Earth to collapse in on itself creating a black hole.

Black hole on scale = infinite weight. Fight me faggots.

>> No.7264539

>>7264536
Can't put a black hole ON a scale.

Checkmate atheists.

Atheists: 0
Pagans: 1

>> No.7264698

>>7264539
But black holes are made of matter with finite mass but infinite density. Couldn't you just measure the mass before it became a black hole?

>> No.7264725

i say 1.5

>> No.7264739

>>7264050
>By your logic if 500g of flies were flying above a set of scales the scales would pick them up.

Are you implying they stay aloft without causing a downwards pressure on the air with their wings?

Are you implying they DO cause a downwards pressure on the air but that the air, being pressed upon, collapses instead of pressing on the scale?

What is your endgame here?

>> No.7264782

>>7264037
The flies aren't inanimate objects suspended in air. They are moving.

Suppose you are in a closed box on a scale. Now you jump up and down. The scale will not at all times display the same weight, but fluctuate. So you will have a closed system that at times weighs less than its enclosed mass.
But since 500 grams of flies are a lot of flies, that effect will probably be negligible.

>> No.7264892

>>7263990
some people just want to see 4chan go nuts.

>> No.7264990

>>7263990
If the lid is shut, 1.5
If the lid is open, 1

>> No.7264992

>>7264782
>So you will have a closed system that at times weighs less than its enclosed mass.

And at times it will weigh more.

>> No.7265014

>>7264530
>>7264516
Its been solved repeatedly in this thread asshat
Net weight would fluctuate around 1.5 Kg

These
>>7264036
>>7264004
>>7264063
>>7264076
>>7264125
>>7264129
>>7264348
>>7264416
>>7264417
>>7264420
>>7264423
>>7264425
>>7264429
>>7264430
>>7264439
>>7264455
>>7264484
>>7264516
>>7264519
>>7264530

are either all from the same person or about 3 people from /b/

/sci/ has some poor quality posting, but this outrageous.

>> No.7265019

>>7265014
It hasn't been solved until someone gets a jar, weighs it, then fills it with flies and weighs it again, then waits for one of the flies to die and weighs that too.

>> No.7265036

>>7265019
Common house fly is ~12 mg
Have fun catching ~47 million flies.

Take pictures too.
Id like to see the 1 kilo jar big enough for that.

>> No.7265053

>>7265036
I'm sure you could scale down the question, and extrapolate.

>> No.7265072

>>7264070
Go get a .001 gram reading scale and go blow on it.

>> No.7265086

>>7263990
>Go get a pool and put it on a scale.
>Take the weight of the pool, write it down.
>jump in the pool and take the weight.
voila! same concept. Water is just heavy enough to stay in the pool without the need of a top, unless you want to count evaporation then fine, let's keep an airtight top on the pool.
I'm going to assume because air is so light that you need to make it airtight to keep the same amount of air in the jar constantly. When you add the flies it adds to the overall weight of the air and would register a change.

Am i correct to assume this?

>> No.7265118

>>7264041
For you.

>> No.7265165

>>7265036
i'm not sure 500 000/12 equal 47 million though