You may have been walking around the walls of various historical cities such as Rome in Assassin's Creed, and enjoying different scenery on the roofs of other people's houses... But the more popular behavior is that you climb up a tall building and find a place with haystacks below, and sometimes a bird is parked next to it-

Then, jump down...

Assassin's Creed seems to like to portray the jumps of the game characters, and after the player "leap of faith" from the above-mentioned place, he usually jumps into a pile of loose straw on the car or on the ground. Then the characters in the game will come out of the haystack like nothing, and continue their assassin career...well, nothing is happening.

What's even more incredible is that the assassins seem to turn into diving (grass) athletes, and they will also perform various difficult coefficient actions in the air - 180 degrees of curling around, somersaults, etc....

Of course, diving athletes dare to jump from the 10-meter platform because there is a deep pool below as a buffer - even so, they need to master the movements and cannot fall on the water sideways... For assassins who love to jump, the loose straw undoubtedly plays a similar buffering role.

But the question is, I have to believe in something to ensure that I will not fall to death after jumping into the haystack?

——Science.

(Of course, there are also those who jump into the water and flowers... but there are forks and other things in the straw pile, which are not within the scope of this article!)

Straw pile without forks

(Because of the laziness of the mapper...ah no, it is the game setting) We will find that the straw pile used for buffering in the game is the same size, whether it is on the ground, on the car, or in someone else's yard...

So in this case, the buffering effect of the haystack on you must be the same, the key is your jump height. The higher the jump height, the greater the kinetic energy converted into by gravity potential energy, and the haystack will absorb part of the kinetic energy, which means it provides a "buffer".

Well, that is, we can try to build a model to calculate (don't be busy with "I choose death", you can ignore those formulas):

Compared to looking at the formula, I'd better jump down... wait!

The Assassin's Creed is missing math?

Because haystacks are the same, we can use fixed haystack parameters to calculate.

First of all, we need to know how much force a man is subject to when he jumps on a haystack. The "extrusion stress" that the straw pile is subjected to can be calculated from this formula:

Where K is the elastic coefficient (that is the spring), V is the volume of the straw pile, P is the "extrusion stress", which refers to aA descending object (that is, the game character you control...) gives the force of the haystack. Given a haystack volume, we can know the amount of pressure it can withstand. This pressure P is:

m is the mass of the falling object, that is, how heavy is the assassin. a represents the deceleration parameter, while A represents the contact area.

When the haystack volume is compressed from volume V1 to V2 by a jumped assassin, add a point to the first equation, and then substitute it with the above equation, we get the volume ratio of haystack V2 (compressed) and haystack V1 (intact):

If you still follow Xiawanjun, you will find that a, which represents the deceleration coefficient, needs to be calculated. According to this formula, a can be calculated from the distance s where the haystack is compressed by the assassin's body, the speed u and the impact time t of the moment the body and the haystack contact:

And because t=u/a, it is simplified to obtain:

Then we will find that this compressed distance s is actually the height change before and after the haystack. Then, using the contact area A of the haystack and the assassin's body, we use the volume changes V1 and V2 of the haystack to represent the distance s compressed by the body. After talking for so long, if you still remember the previous formula (1) and formula (3) (Xiawanjun knows you definitely don’t remember), then we can deduce it to the end—

You will eventually get a formula like this: