

The Physics of The Hulk’s Jump - ghosh
http://www.wired.com/wiredscience/2012/05/the-physics-of-the-hulks-jump/

======
drostie
TL;DR: The Hulk is maybe around 250 kg and jumps atop a 120 m building in the
movie, which using E = m g h means that he jumped with a kinetic energy of
~300 kJ. He pushes through a distance of around one meter, so using W = F Δx
we can estimate his force as ~300 kN. Normal male feet have a surface area of
500 to 800 cm² [1], so if we use 1000 cm² for convenience, we get 3 MPa. The
compressive strength of concrete is ~10 MPa, so we shouldn't expect the jump
to crack concrete, but it might, if his peak force is higher and is exerted
through the balls of his feet.

[1] (In my case, this is stolen from
<http://dx.doi.org/10.1016/j.apergo.2008.08.004> \-- the blogger above tries
to estimate his own feet but I have access through such paywalls. This surface
area is given for one foot, but includes the top, so it's basically the same
as two feet.)

~~~
Peroni
_The Hulk is maybe around 250kg_

There are many derivatives of 'Hulk'. The one depicted in this movie, and the
most common hulk is Savage Hulk.

Savage Hulk's weight is estimated to be approximately 1,150lbs or roughly
520kg.[1]

[1] <http://marvel.wikia.com/Hulk_(Robert_Bruce_Banner)>

_damn you for making me publicly reveal my obsession with a fictional
character_

~~~
drostie
Sorry if I offended. The article said 300kg and I "toned it down" to 250kg to
better match with the idea that the Hulk in the picture basically looks like
two heavyweight boxers in one. I see that the official number is closer to
four heavyweight boxers, and I apologize.

~~~
Peroni
Apology accepted. ;-)

It would be interesting to see it re-calculated with the accurate weight. His
average height is also estimated at around 8 feet if that helps. No records
exist to indicate his foot size however the do appear to be disproportionately
large for his size.

~~~
drostie
According to the Marvel Wikia he can easily lift 90-100 tons. Tons in all
their forms are about 1000 kg and on Earth weights go like ~10 Newtons = 1 kg,
so he can easily muster 1000 kN of force when lifting. This suggests that he's
plenty capable of enduring the now-600 kN of force from his legs that he needs
to jump to the top of a 120m building. It still takes him about a meter to do
it, and he now produces 6 MPa of pressure on the ground -- less if his feet
are much larger, but again he might jump from the balls of his feet,
decreasing their surface area.

The only surprising thing is that he goes from 0 to 120 mph in at most two
meters of pushing (assuming he somehow ducks down to the point where his
center of mass is only 2ft above the ground -- that makes this an upper
limit). That means that he completes the jump in only about 75 milliseconds,
or half of a human reaction time. You have to imagine that he ducks down, and
then before you can blink, he is already off with full automobile speed flying
into the air. The effect on the ground is basically the same as a car at 70
mph crashing into a concrete barrier; you can see a couple cars crashing into
walls done by the Mythbusters at this link:

<https://www.youtube.com/watch?v=r8E5dUnLmh4>

The wall escapes pretty much unharmed, though I don't know what it's made out
of.

The question posed is whether the concrete cracks, and it really depends on
what's beneath the concrete. The problem is that concrete is basically made up
of packed rocks held together with glue. This gives it an odd structural
property: it is much easier to pull it apart, structurally speaking, than it
is to compress it. Concrete does very well under compression, very poorly
under tension. Bending a slab of concrete means putting compression on the
near side, where the rocks have to come together, but putting tension on the
far side, where stuff bends outward and apart. Whether the Hulk breaks the
concrete depends very strongly on what's happening on the outward side -- does
it generate cracks which propagate all the way up through the concrete? That's
much harder to answer.

------
chris_wot
Some of the comments on this article are hilarious! I especially love the one
where someone says that they work near the building he jumped at - and they
can confirm that he didn't break the concrete.

I do think that the most convincing explanation came from the comments section
as well. The explanation is that:

"The Hulk's Mass and Power have no limit as he drives his power from Anger.
Nobody can quantify Anger as their is no way to measure how angry one can get
and there is no upper limit to Anger."

Makes sense to me!

------
machrider
Hah, this is the one thing I remember from that trailer (aside from Scarlett
Johansson) - the Hulk's ridiculous jump. Great beanplating in this article.

~~~
mattdeboard
"beanplating" was a new one for me:

<http://www.urbandictionary.com/define.php?term=beanplating>

------
moreati
I tried the same a few years back for Batou/Ghost in the Shell
[https://docs.google.com/spreadsheet/ccc?key=0At5kubLl6ri7dEp...](https://docs.google.com/spreadsheet/ccc?key=0At5kubLl6ri7dEpHQW9jbTVQVFB3WTBmbGozajRSWUE).
This article does a much better job though.

------
estacado
The jump in Ang Lee's Hulk (played by Eric Bana) is even more ridiculous.

