Be professor

College professors teach more to their six year olds than to their students. And taxpayers still pay for your wages. Sad!

Then their falling bodies are pushing down the air.

>3am sleeping
>hear a rumbling
>getting louder
>look outside, see airplane cruising at an altitude of 35,000 feet
>gonna fly right over my house
>FUCK
>run outside and watch my house be crushed by the downward pushed air.
>plane keeps flying, leaving a destructive trail of downward pushed air in it's path
But yea bro it's 1.5 kg moron

this is a really poor statement

No, the scale would show 1kg in that case until they hit the ground.

As long as the center of mass of the jar+flies system stays constant then the scale shows 1.5kg.

finally someone, who understands basic physics

You and your son are fucking retards.

wrong, any value it might have is meaningless

the force generated by the plane is really well distributed in the atmosphere, so what you are implying is sheer retardness

it acutally is a really nice problem

the task was to find what the scale read, so your existence is meaningless

>t. nihilist

kek typical brainlet, "i can't solve dis s1mple ez ekwuazion is da prohfesirs fawlt!!1!11one"

But then what constitutes the "jars+flies system"?

If you removed the lid would the scale drop by both the lid amount and the flies, or just the lid (so long as the flies remained within the jar)?

you are actually retarded

I'm not a physicist, but that's how I understand it :
Since the fly stay in the air, they are somehow transfering their weight to the air that supports them. That weight is then applied on the scale via air pressure.

If you open the lid, then the weight will stay the same, except if the fly leave and their weight gets distributed on a larger area.

nice trolling m8;
I took your bait.

...

No, it needs speed relative to the air that supports it, not the ground.

kekd

The answer is the sum of the first 2 milion primes

Of course it is!

The real question is, how do you get half a kg of flies into such a small jar?

Depends, are the flies sleeping?

How much does the air weigh

The answer is how the fuck are you fitting .5 KG of flies into a 1 KG jar... the flies would likely be so jammed together that they couldn't move and thus would weigh the .5 KG

Also what does a compacted group of flies look like?

>metric system

How the fuck am I supposed to do math in those fucked up units?

>fucked up units

found the murifat. The metric system is great

your image is misleading OP

Mythbusters did this shit in like 2009.

youtu.be/lVeP6oqH-Qo

Jump to 2:18 for them doing it with an RC helicopter for better data.

Weight of the jar will not change unless the lid is removed. If the lid is removed, the weight of the jar will drop by the weight of the lid, plus a percentage of the weight of the flies determined by the amount of air displaced by their wings that is pushing outward or upward and out of the jar instead of downward.

Agree with 1kg. But is that really the correct explanaition?
Suppose the flies behave like helicopters, so center of mass stays constant but the scale would show 1kg. Isn't the explanation that the lift force compensates gravitational force? It's basically about the difference between weight (1kg) and mass (1.5kg), isn't it?

Oy! I'm Murican, and am fine with metric.
is just a contributor to the 7%.

This is the only correct answer. However, it is the average of the weight. Every time they flap their wings the pressure makes it weight more for a brief moment then less for a brief moment. The average of that will be 1.5kg. Most scales won't be able to show that weight change since it is so insignificant. There's also the problem of more than one creature flapping its wings. The original experiment used a single bird to get these types of results.

>this thread again
>all these complete fucktards

Do you think a scale displays milliseconds you fucking moron???? Go back to kindygarten retard

In theory there should be 1.5, in reality the downwards air produced by the birds wings won't flow perfectly the floor surface, there will be turbulence and fluid friction along the way meaning it will weigh very slightly less than 1.5, and the difference in weight is made up by increased temperatures

>be me
>come to Veeky Forums for the first time after a long absence
>"5 flies can generate half a kilogram of downward thrust"
nevar change

Who says we're not the smartest board on Veeky Forums?

31.381.137.530.481 ?

>He thinks weight and mass both have units of kg

SI masterrace amirite senpai?

They can if there's enough of them to weigh 0.5kg, which the pic has established.

Yes this is correct if the jar is sealed. And ideal conditions are assumed.

It takes exactly as much force to fly as the weight of the flies. If they were supplying less force than their weight they won't go up at all. The weight that is lost is gained back by the force they send downwards to fly.

This is all assuming ideal conditions. In particular that the force supplied by the flies goes straight down with none going off to the sides. Also if the jar isn't sealed the air that mediates the force can go upwards due to pressure differences. So in realistic circumstances, regardless of whether the jar is sealed, the weight measured by the scale would be a little less than 1.5 kg.

Bernoulli's principle says that if the lid is on the jar then the air pressure will stay in the jar, so the flies being in the air doesn't matter and the jar would weigh 1.5kg.
If the lid isn't on the jar then the air pressure can escape and the jar would only weigh 1kg if the flies were flying.

Somewhere in between 1kg and 1.5, it would fluctuate. The push of the flies wings down is going to be negligible, the air they are pushing on doesn't travel straight down, it undergoes turbulence, and pushes on the walls, floor and lid of the jar. The force of their wingbeats gets diluted by the time it hits any given wall of the jar, and it would be negligible. However, any time one of the flies landed, it would put the weight closer to 1.5kg.

What if the lid has breathing holes? If it's an air-tight lid, wouldn't the flies die? poor flies

Then it'd weigh somewhere between 1kg and 1.5kg, cause only some of the pressure would be released

they're not in equilibrium though DUHHH

the jar might just be really tall and they're speeding upwards

welcome back, friendo

Time average is 1.5 kg
A discreet reading will be some value greater than 1.0 Kg

Stop being an idiot. No one implied that. You where just being taught something you didn't know.

bbc.com/news/science-environment-30797983

TROLLS BTFO

Hnestly though, why isn't this video the first thing posted?

This is like the 102nd thread for this copy pasta. The turn around rate for Veeky Forums is too high. There are too many newfags. The real question is that why are you the only person to reply to that post?

>physics problem
>"im not a physicyst BUTTTT"
Just stop kid

Is the jar sealed?

DON'T CALL ME "KID", SON.

Really cool, never seen this vid. Thanks

It's exactly the opposite, if the jar is sealed no additional weight will be measured because the system is closed and any force will only be exerted on the boundaries of the jar. If not sealed we will measure 1.5kg.
If thats too abstract for you, imagine the whole thing upside down with the opening on the ground an the flies exerting a force of say 2kg trying to lift the jar, if the flies weight are less than 1kg they would lift it. Now you seal the jar and by your logic it should start to levitate with no air flow whatsoever, that would be really stupid to assume wouldn't it?

Your wife's son is an asshole.

Kek

Wrong, flies generate antigravity to stay afloat so it's 0.5kg.

Did you do the experiment?

What if we have a sealed jar that weighs 0kg, and all the flies try to fly upwards through the lid?

>It should start to levitate
There is no net force in given system

This is retarded.

Their wings would have to be completely in sync to be 1.5 kg and even then it'd fluctuate on the down and up stroke of each wing beat.

>professor
>shitposts of Veeky Forums while Farming his exams out to 6 year olds
>mocks his students for not knowing more about physics
>neck yourself. You're the problem dumbass.

Replace the air and flies with water and fish.

1kg

>t. 93% here

Why is everyone else so retarded user? I feel alone :(

Go away trump

If we had a long enough treadmill, would it accelerate?

I'm afraid you feel alone because you and him are actually the retards that do not understand Newton's third law:

rsif.royalsocietypublishing.org/content/12/104/20141283

Just wait for them to land and it will for sure weigh 1.5.

The flies weigh half as much as the jar?!

Did these flies come from Veeky Forums or something?

>Implying an aeroplane takes off using powered wheels

it's 0 kg if you're in space

flies raise the density of the air in the same way replacing the air with another gas would, so i'ts 1.5 kg

But what if the jar is a car and the fly flies through a window in the car?

...

When you hold your hand out five feet in the air and slowly move it down, the air pressure directly under your hand may increase, but surely the air pressure at the ground level is unaffected and remains the same as it's surroundings.

I posit that the flies will indeed affect the distribution of pressure in the air but the net result on the bottom surface of the jar will be negligible.

In order to be more certain of this, the dimensions of the jar would need to be a known quantity.

>open system vs closed system
I posit that you are retarded.

The answer depends on how the scale is calibrated.

>not having a current NIST-traceable calibration
pleb NEET detected

Who calibrates the calibrators?

That question makes no sense, and I therefore will not respond to it.

...

im blowing on my scales but nothings happening helppp

>Also what does a compacted group of flies look like?
like this probably

googled "dead flies"

Your*

its 9.81kg/s^2

It's non intuitive that the flies in flight contribute to the weight. I don't have a problem with people not getting the problem right.

If you didn't teach the principle before giving out the question you're a total asshole.

See