If superpowers were real: Flight - Joy Lin

Prevodilac: Mile Živković Lektor: Anja Saric

If humans could fly,

Kada bi ljudi mogli da lete

without tools and machines,

bez alata i mašina,

how fast do you think we would go?

šta mislite, koliko brzo bismo išli?

As of 2012, the world record

Od 2012, svetski rekord

for fastest short-distance sprint speed

za najveću brzinu trčanja na kratkoj udaljenosti

is roughly 27 miles per hour.

je oko 43 kilometra na čas.

Running speed depends on how much force

Brzina trčanja zavisi od toga

is exerted by the runner's legs,

koliko sile ispoljavaju noge onoga ko trči,

and according to Newton's Second Law of Motion,

i po Njutnovom drugom zakonu kretanja,

force is the product of mass times acceleration.

sila je proizvod mase puta ubrzanja.

And Newton's Third Law states

A Njutnov treći zakon kaže

that for every action,

da za svaku akciju

there is an equal and opposite reaction.

postoji jednaka i suprotna reakcija.

So, that means running requires

To znači da je za trčanje potrebno

having a ground to push off from,

tlo da se od njega odguramo

and the ground pushes back against the runner's foot.

i tlo se odupire od stopala onoga ko trči.

So, flying would actually be

Letenje bi zapravo bilo

more similar to swimming.

sličnije plivanju.

Michael Phelps is currently the fastest human in water

Majkl Felps je trenutno najbrži čovek u vodi

and the most decorated Olympian of all time.

i Olimpijac sa najviše odlikovanja u istoriji.

Guess how fast he swims?

Pogodite koliko brzo pliva?

The answer may surprise you.

Odgovor će vas možda iznenaditi.

His fastest recorded speed is

Najveća zabeležena brzina

less than 5 miles per hour.

je manja od 8 kilometara na čas.

A child on the ground can easily outrun

Dete na površini lako može da bude brže

Michael Phelps in water,

od Majkla Felpsa u vodi,

but why is that?

ali zašto je to tako?

Well, let's go back to Newton's Third Law of Motion.

Pa, vratimo se Njutnovom trećem zakonu kretanja.

When we run, we move forward

Kada trčimo, krećemo se unapred

by pushing against the ground with our feet

tako što se odupiremo od zemlje svojim stopalima

and the ground pushes back,

a zemlja se odupire nazad

propelling us forward.

i gura nas unapred.

The ground is solid.

Zemlja je čvrsta.

By definition, it means the particles

Po definiciji, to znači da su čestice

are essentially locked into place

zapravo fiksirane u prostoru

and must push back instead of getting out of the way,

i moraju da guraju nazad umesto da se sklone,

but water is liquid and flows easily.

ali voda je tečna i lako teče.

When we move our limbs

Kada pomeramo svoje udove

to push back against the water,

da se odgurnemo od vode,

a part of the water molecules

deo molekula vode

can just slide past one another

može samo da proklizne jedan pored drugog

instead of pushing back.

umesto da guraju nazad.

Now, let's think about flying.

Razmislimo sada o letenju.

Air has a lot more free space

Vazduh ima puno više slobodnog prostora

for particles to move past one another,

gde čestice mogu da se kreću jedna pored druge,

so even more of our energy would be wasted.

tako da bi se protraćilo još više naše energije.

We would need to push a lot of air backwards

Morali bismo da guramo mnogo vazduha nazad

in order to move forward.

kako bismo se kretali unapred.

Astronauts move around in shuttles

Astronauti se kreću u šatlovima

in zero gravity when they're in outer space

u nultoj gravitaciju kada su u svemiru

by pulling on handles installed on the ceiling walls

tako što vuku ručke na zidovima plafona

and floors of the shuttle.

i podovima šatla.

Now, imagine you were given the ability to float.

Sada zamislite da imate mogućnost lebdenja.

How would you move around in the middle of the street?

Kako biste se kretali nasred ulice?

Well, you wouldn't get very far

Pa, ne biste se puno odmakli

by swimming in air, would you?

plivajući u vazduhu, zar ne?

Nah, I don't think so!

Ni ja ne mislim tako!

Now, assuming you were granted the ability to float

Recimo da vam je data mogućnost lebdenja

and the speed to move around efficiently,

i brzina da se efikasno krećete,

let's discuss the height of your flight.

popričajmo o visini vašeg letenja.

According to the Ideal Gas Law,

Po Zakonu idealnog gasa,

P-V N-R-T,

P-V N R-T,

pressure and temperature has a positive correlation,

pritisak i temperatura su u pozitivnoj korelaciji,

meaning they increase and decrease together.

što znači da se zajedno povećavaju i smanjuju.

This is because the air expands in volume

Ovo se dešava zato što se vazduh širi u zapremini

with less pressure,

sa manje pritiska,

so the molecules have more room to wander around

tako da molekuli imaju više prostora da lutaju

without colliding into each other and creating heat.

a da se međusobno ne sudare i stvore toplotu.

Since the atmospheric pressure is a lot lower

Pošto je atmosferski pritisak mnogo niži

in high altitudes,

na velikim visinama,

it would be freezing cold

bilo bi neverovatno hladno

if you were flying above the clouds.

kada biste leteli iznad oblaka.

You'd need to wrap yourself up

Morali biste da se zamotate

to keep your core body temperature

kako biste održali temperaturu tela

above 95 degrees Fahrenheit,

iznad 35 stepeni Celzijusa,

otherwise you'd start shivering violently,

ili biste počeli snažno da drhtite

gradually becoming mentally confused

i postepeno postajete mentalno zbunjeni

and eventually drop out of the sky

i na kraju biste pali s neba

due to loss of muscle control

zbog gubitka kontrole mišića

from hypothermia!

od hipotermije!

Now, the Ideal Gas Law implies

Zakon idealnog gasa navodi

that as the pressure decreases,

da kako se smanjuje pritisak,

gas volume increases.

tako raste zapremina gasa.

So, if you were to fly straight up too quickly,

Kada biste leteli pravo previše brzo,

inertni gas u vašem telu bi se naglo raširio

the inert gas in your body would rapidly expand

the way soda fizzes up when shaken.

kao što se gazirano piće zapeni kada ga protresete.

The phenomenon is called "the bends,"

Ova pojava se zove aeroembolizam,

decompression sickness,

dekompresiona bolest

or "divers disease"

ili "bolest ronilaca",

since deep sea scuba divers experience this

pošto ronioci na velike dubine ovo iskuse

when they come up too quickly.

kada prebrzo izađu na površinu.

This results in pain,

Ovo za posledicu ima bol,

paralysis,

paralizu

or death,

ili smrt,

depending on how foamy your blood becomes.

u zavisnosti od toga koliko se zapeni vaša krv.

Okay, well, let's say you want to fly

U redu, recimo da želite da letite

just a few meters above the ground

samo nekoliko metara nad zemljom

gde još uvek možete videti putokaze

where you can still see the road signs

and breath oxygen with ease.

i disati vazduh s lakoćom.

You'll still need goggles and a helmet

Još uvek će vam biti potrebni naočare i kaciga

to protect you from birds,

da se zaštitite od ptica,

insects,

street signs,

insekata,

uličnih znakova,

electrical wires,

električnih dalekovoda

and other flying humans,

i drugih ljudi koji lete,

including flying cops

uključujući i leteće policajce

ready to hand you a ticket

koji su spremni da napišu kaznu

if you don't follow the flying rules, buddy.

ako ne pratite pravila letenja, druškane.

Now remember, if you have a collision mid-air

Zapamtite, ako usred vazduha imate sudar

that knocks you unconscious,

od kog se onesvestite,

you would experience free fall

iskusili biste slobodan pad

until you hit the ground.

dok ne biste udarili tlo.

Without society or the laws of physics,

Bez društva ili zakona fizike,

flying would be a totally awesome ability to have.

letenje bi bilo sjajna sposobnost.

But, even if we could all just float around

Ali čak i kada bismo mogli samo da lebdimo

a few feet above the ground

nekoliko metara nad zemljom

and only moving at a snail's pace,

i krećemo se brzinom puža,

I'm telling you, it's still a cool ability that I'd want,

kažem vam, opet je to super sposobnost koju bih želeo da imam,

wouldn't you?

a vi?

Yeah, I thought so.

Tako sam i mislio.

Now, which superpower physics lesson

Sada, koju ćete lekciju o supermoćima iz fizike

will you explore next?

istražiti nakon ove?

Shifting body size and content,

Menjanje veličine i sadržaja tela,

super speed,

superbrzina,

flight,

letenje,

super strength,

nadljudska snaga,

immortality,

besmrtnost

and

ili

invisibility.

nevidljivost.