Have you seen this man?

Not so fast.

Hi, my name is Rhett Allain.

[Announcer] Rhett is a physics professor

at Southeastern Louisiana University.

Today I'll be breaking down amazing feats of physics

from superheroes in movies and television.

Superhero landing, Deadpool.

Go get some.

Superhero landing.

She's gonna do a superhero landing.

Wait for it.

Whoa, superhero landing.

You know, that's really hard on your knees.

You know, one of the great things about Deadpool

both in the comics and in the movies

is that he breaks the fourth wall

and interacts with the audience.

I know, right?

In this case, he talks about the superhero landing.

Superhero landing.

She's gonna do a superhero landing.

Wait for it.

The idea is a superhero lands with one knee,

one fist and a foot on the ground.

So three contact points, but it's a very sudden move.

It's not like a normal landing, it does look really cool

and it happens all the time.

And is that better than

the way a normal person would hit the ground?

The answer is no.

You know, that's really hard on your knees.

Totally impractical, they all do it.

So you gotta think about the forces acting on a person

while they're landing from falling from somewhere.

The key is to have the force as small as possible.

One way to do that,

is to increase the distance over which you stop.

So if I jump and land on the ground,

I let my knees bend,

and my center mass moves down while my knees bend

increase the distance over which I stop

and decrease the force.

There's a thing called a parachute landing fall,

and you don't even stand up.

You hit, you bend down, you roll over on the ground,

and you increase the distance over which you stop even more.

That's the best way to do it.

The superhero landing, it's just gonna be a bad idea.

And we all know how this turned out.

Kinetic energy, Black Panther.

Hey, look at your suit.

You've been taking bullets

charging it up with kinetic energy.

[engine roaring]

Kinetic energy is a quantity you can use

to describe objects in motion.

We have momentum, which is mass times velocity

and then there's kinetic energy,

which is one half mass velocity squared.

Show off.

You know, kinetic energy isn't a real thing.

It's a way to view nature.

It's a way to view interactions.

So anything that's moving would have kinetic energy.

If I take a baseball and I throw it,

it's moving, it has mass, so it has kinetic energy.

Black Panther's suit somehow

has an interaction between the bullet and the suit

to take the kinetic energy of the bullets

and store it in some type of internal battery.

And then once he has enough energy stored up,

he can release it in an energy polt of some type

to do whatever he wants.

I'm not sure exactly how it works.

That's what makes him Black Panther

and the technology of Wakanda is beyond me

to fully understand.

Recoil, Wonder Woman.

[gun fires]

So what is recoil?

Suppose I am standing on a frozen lake

and I have a basketball or some heavy weighted ball

and I throw the ball.

Well, the balls momentum is gonna change

because I exert a force on it.

But the ball pushes back on me with the same force.

So I'm gonna have the exact same change momentum

that's gonna make me move back.

Of course, it makes complete sense.

This is the idea of recoil.

When you throw something one way

you go back the other way.

So a bullet has momentum.

It's moving, it has mass has velocity,

but it turns out that it's moving really fast

but it has pretty low mass

and it doesn't have that much momentum.

If you collide a bullet with a bracelet

or a person in some way,

then that person would have to recoil

with the same momentum.

But the person has such a large mass,

the recoil velocity would be super tiny.

And so you don't really get recoil from normal bullets

when they hit people.

So in this case, Wonder Woman deflecting a bullet

it should be fine.

Is there anything else you wanna to show me?

Contact area, Justice League.

I'll take the ones on the right.

The Superman building thing is impossible.

Forget about the flying, forget about the super strength.

Even with that he couldn't do this.

So imagine you had a jello cake.

It's like a big blob of jello this big.

Is this a bad time to bring up my blood sugar?

And you want to lift up the jello with a toothpick

by pushing on the bottom,

the toothpick would just go right through the jello.

On top of that, the jello would probably break in half too.

So both of those things are a problem.

Superman's pushing in the middle of the building,

trying to support the whole thing,

he would just poke right through the whole thing

and the building would fall.

If he wants to actually lift the building,

he needs to increase the contact area,

either get bigger hands,

which that's probably not gonna happen.

Or he could possibly have some cables

that attach to multiple locationss on the building,

and then lift it from the top.

Maybe it doesn't look as cool,

but it'd be more plausible at least.

Weird in so many ways.

Strength, Spider-man Homecoming.

At the beginning, Spider-Man uses his webs

to connect one side of the boat to the other

in an attempt to prevent it from falling apart

and it doesn't work.

Yeah, Spider-Man.

It could be any number of reasons.

Particularly, he just doesn't have enough webs

to actually exert enough force between the two halves

to prevent them falling apart.

The ultimate tensile strength,

the point at which the tension breaks

where the string breaks for Spider-Man's webs.

I mean, you first need to know what it's made up

and then you need to know the diameter of it.

It's really difficult to estimate how much that could be.

A better way to approach this,

would be to calculate the tension

that he exerts on the boat when it breaks.

The more they lean,

the greater the gravitational force is on that piece

to pull it apart and you need a lot of force

to keep these two things together

and maybe his webs just aren't strong enough to do that.

[Karen] Great job, Peter.

You're 98% successful.

98?

I suspect the 98% means

that the total force needed to keep one side of the boat up

is 98% of what you need to prevent it from falling over.

If the force isn't great enough,

the boat tilts and it stretches that web

and eventually the web breaks

and then you have no force from the web

and that makes more webs break

and have a sort of cascading failure.

Hi, Spider-Man.

Band practice through?

The Iron Man suit may be more successful

at pushing the boat back together for a couple of reasons.

Number one, it's possible

that his many micro thruster rockets

that attach to the side of the ship

are just stronger than Spider-Man's webs.

The second big thing

is that those forces can keep moving as the boat moves,

whereas Spider-Man's force is a static force.

Once you stretch past that, it can't pull it back together,

it just prevents it from falling apart further.

The ship floats

because it prevents water from getting inside

and makes it overall effective density less than water.

Once you violate the integrity of the hole, game's over.

That thing is gonna sink really fast.

I don't think Spider-Man is gonna have enough time

to push it back together,

I don't think Iron Man's gonna have enough time

to push it back together.

Now, it's just a movie so we're okay with that.

What do you want me to do?

I think you've done enough.

Terminal velocity, Captain America, The Winter Soldier.

Was he wearing a parachute?

No.

No, he wasn't.

[dramatic music]

So when Captain America jumps out of the plane,

there's really two forces that come into play.

The first is the gravitational force that pulls him down.

But there's another force as he starts to fall

and increase in speed, there's an air resistance force.

He's colliding with the air molecules

and those air molecules push back on him

in the opposite direction that he's moving.

And in fact, it gets to the part

where it is the same as the gravitational force.

Now he has an upward pushing force

and a downward pushing force

that are equal in magnitude.

With equal magnitude forces,

he moves at a constant speed.

We call this terminal velocity

because he doesn't get any faster.

When Captain America first leaves the plane,

he starts off in a standard skydiving position.

This position allows the largest surface area

for the highest air resistance force

and therefore the lowest terminal velocity.

It also allows you to move your hands in a way

that you could actually control your motion

by pushing the air in different directions.

Towards the end of the jump,

he actually goes into a more vertical position.

This decreases the surface area that collides with the air

and makes him fall even faster.

Dude, you're a lot heavier than you look.

I had a big breakfast.

He wants to hit the water feet first.

So he flips over, hits the water feet first

in like a pencil, dive or pencil jump

and the nice thing about the feet first vertical position

when hitting the water,

is that it will make him penetrate

the deepest into the water

which increases the distance over which he stops

and decreases the stopping force

and gives him a better chance of surviving.

I mean, it's Captain America,

so he's probably gonna survive no matter what.

Net force, Iron Man three.

Listen to me, see that guy?

I'm gonna swing by, you're just gonna grab him.

I'll electrify your arm,

you won't be able to open your hand.

We can do this Heather.

Once you start having multiple people

in a chain hanging together, the person on the bottom,

they're just hanging like a normal person.

The next person has to pull

with the force equal to their own weight

and the force of the person pulling down below them,

which is their weight.

The third person has to pull with the force of three people

and you can see,

it starts getting really large and uncontrollable.

Iron Man wants to solve this problem

by essentially electrically shocking their muscles

into contracting so they can't let go.

I'll electrify your arm,

you won't be able to open your hand.

I don't think that would work

for a number of reasons.

I get a lot of this, it's okay.

First if you get like five people in a line,

it's probably not just about muscles,

things start to break in human arms and it wouldn't work.

The second thing is that

you can have an electrical shock

make people's muscles contract

but the problem is that you normally need a closed circuit

you need a path for the current to go there

and all the way back and he just has a chain.

There's no way for the current to get back to Iron man

and use his power supply to force this shock gripping.

Nice guys work guys.

Excellent, good team effort all around, go us.

Disintegration, The Boys.

Poster.

Hey, don't you ever besmirch Billy,

I can't stop, I can't stop.

I can't stop, I can't stop, I can't stop.

So A-Train's running really quick

and he runs into a girl, what would really happen?

I mean, it's such a hard question

because it really depends on A-Train.

Is he invincible

or is he like just a really fast, normal human?

If he's a really fast, normal human,

colliding with a stationary human,

they would both have the same amount of damage

because if he pushes on her with a force,

she pushes back with the same force.

So whatever happened to her would happen to him.

In the clip, she just turns into goo.

So clearly, he has some other powers

other than just being super fast.

Would he just push right through her

or would which she recoil?

Well, it really depends on again,

how fast he's going and how he actually hits her.

If one part of him hits her, before the rest of him does,

he could essentially poke through her.

I know that's kind of gross

and once he's done that

he kind of disables the integrity of her body,

such that it's possible

she could go splattered all over the place.

Oh, watching that clip,

there is one issue that is weird.

If he's running this way and hits her,

why did some of the blood go back on on her boyfriend?

It appears that he hitting her

would push all the blood in the same direction

he was moving.

So, I mean, it's kind of a gross clip,

but it shows an important point in the story

and that the superheroes aren't always nice guys.

Sorry about what happened to your girlfriend, all right?

Running on water, The Incredibles.

[laughs]

[dramatic music]

So let's say you wanna run on water,

you need an upward force

to counteract the gravitational force that pushes down.

One way to do this would be kind of like slapping the water.

If I hit the water with my hand or foot,

then the water pushes up on me,

but it's not a huge force and it doesn't last for very long.

I don't know, I don't know how he does it.

That means that you have to hit the water really hard

and then hit it again really hard.

So you really got to move your feet

back and forth super quick

in order to get this whole thing to work.

You must have been booking,

how fast do you think you were going?

I mean, I don't think a normal person can do it,

but clearly Dash can do it.

So when he stops and kind of hovers there

for a little bit on the water,

I think it's the Wile E. Coyote effect.

So if you remember,

Wile E. Coyote would chase the Road Runner.

He'd go off a cliff, and then he'd say,

Well, I just realized I'm not on the ground.

And then he falls.

It's very dramatic and it's kind of funny,

and I think that's exactly what happens with Dash.

Of course, as soon as he stops

he would start sinking into the water and fall down.

But it's comedic effect.

[Robert] Well, what are you waiting for?

I don't know, something amazing I guess.

Flying, Iron Man.

Ready,

and three,

two,

one.

In this scene,

Tony Stark is testing out his Iron Man suit.

He had built one before,

but it wasn't as sophisticated as this one.

Not bad.

So he needs to make sure

that thrusters are configured properly to allow him to fly.

So imagine you had like a pencil

and you wanna hold it on your hand right here,

and you're holding it from the bottom.

If you push up, it's very easily just gonna tip over.

And so rockets from the bottom of a device

are a little problematic.

Real rockets do this by having gimbals on the thrusters

that can change the direction very easily.

But there's another solution,

and that's to have a higher thruster

and that's what Iron Man does with this hand.

When his hands are higher up,

then the thrust is above the center mass,

and it makes it much more stable.

And on top of that,

he has his hand further apart from his body

and that further increases stability.

In fact, there's a guy that has

real life Iron Man suit type flying,

and he uses jets on his hands,

and it's much more stable than putting them on your feet.

So this is exactly how I would do it

if I was gonna do it.

Impact force, Guardians of the Galaxy.

No Groot, you can't.

You'll die.

I'm not sure what exactly Groot does in this case,

but if he stays completely rigid as a rigid sphere,

then it's not really going to help people inside.

Now, if he has some type of,

I don't know, in a car, we call it a crumple zone

where the car actually changes dimensions

and crumples up during a collision.

This would increase the distance over which it stops,

which would decrease acceleration

and it would make it more survivable for the people inside.

Another aspect of this cage idea

could be one to protect from things like debris

that gets thrown around during the crash.

That would definitely work.

I mean, if you have a shell around you

and something comes flying in, that shell could block it.

It's not just that you want wood to be strong,

you definitely want it be flexible group.

Groot maybe he's like, can pick,

maybe he can pick what kind of wood he grows into

so he could make it both flexible and strong,

depending on the situation.

Thank you.

See, Groot's, the only one of you who has a clue.

If I was Groot, which I'm clearly not Groot.

I am Groot.

I would have like things go down below the sphere

that you couldn't see

and have those impact with the ground first

and have them kind of be your crumple zone

and then keep the sphere rigid to protect from debris.

And then you'd have a rigid part as a sphere

and then a springy part below.

Force pairs, The Defenders.

So in this scene from The Defenders,

we have Jessica Jones, super strong,

and Luke Cage, super strong.

And when they punch,

they really would have to consider what angle they push at.

If I push with some super large force,

then that same force is gonna be applied to me

because forces come in pairs.

Forces are always an interaction between two objects.

So if I punch horizontally,

the person could go flying across the room,

but I'd go flying back the other way

and that may be effective, but it wouldn't look cool.

There's a better way to punch.

If I was a super powered puncher and I punched up,

then that person would push down on me

and I would get pushed into the floor,

but I would not get pushed back.

So if you're a super powered person,

you can't just go around punching like a normal person,

you have to think about the consequences of your actions.

But we should probably all do that anyway.

Jessica? Luke.

[Luke] How you been?

Long story.

X-ray vision, Man of Steel.

Are you alright Clark?

So this is the part where Clark Kent

starts to realize that he has powers

and one of those powers is X-ray vision.

How does X-ray vision work?

I think the first question is, how does vision work?

We see things because light reflects off of them

and enters our eye.

Or maybe it's a light source itself,

but light has to enter your eye in order to see things.

X-rays are just another type of light

with a smaller wavelength than visible light.

But in this case, how does Superman have X-ray vision?

Is stuff coming out of his eyes

or is stuff coming into his eyes?

If X-rays are coming out of his eyes,

he can't see them, it's just shooting out.

There are X-rays around, background radiation.

It's not very much

and that could pass through people's bodies

and he could see them.

But overall, it's definitely a problematic thing

to be able to see through people with just your eyes.

Windup, Avengers Endgame.

I knew it.

So Captain America has Thor's hammer,

and he's trying to hit Thanos,

he could just hold the hammer

and swing his whole arm and hit him

but by winding up the hammer first,

it's going in a circular motion,

the hammer is actually going at a greater Speed.

If he times it just right, his arms moving up

and the hammer is moving up relative to the hand.

So that gives it a much greater speed

on impact with Thanos' head.

So greater impact speed would mean a greater impact force

and hopefully knock him down in this case.

There's no real benefit to spinning it multiple times,

except for the main benefit that it looks cool.

And if you're a superhero, and you're in,

you know, a big battle number one, you gotta look cool.

Give me that.

You have the little one.

[Announcer] Conclusion.

I think these are just great examples

of even if they're not real physics,

physics is still all around us.

And we can find it in the most trivial things,

even superhero movies.

So physics in movies, I'm all for it,

even if it's not 100% correct,

because what if you did have completely realistic physics

in superhero movies?

Might not be that much fun.

We go to the movies, not for the correct physics.

We go there because they don't have correct physics really

and I'm fine with that.