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How does a cat land on its legs when dropped?
Physlink.com ^ | 2005 | unk.

Posted on 01/24/2005 10:53:22 AM PST by FoxInSocks

How does a cat land on its legs when dropped?

ANSWER 1:

Cats have the seemingly unique ability to orient themselves in a fall allowing them to avoid many injuries. This ability is attributed to two significant feline characteristics: A “righting reflex” and a unique skeletal structure.

The “righting reflex” is the cat’s ability to first, know up from down, and then the innate nature to rotate in mid air to orient the body so its feet face downward. Animal experts say that this instinct is observable in kittens as young as three to four weeks, and is fully developed by the age of seven weeks.

A cat’s “righting reflex” is augmented by an unusually flexible backbone and the absence of a collarbone in the skeleton. Combined, these factors allow for amazing flexibility and upper body rotation. By turning the head and forefeet, the rest of the body naturally follows and cat is able reorient itself.

Reports of cats surviving falls of several stories in height have coined the expression of cats having “high rise syndrome.” Like many small animals, cats are said to have a non-fatal terminal falling velocity. That is, because of their very low body volume-to-weight ratio these animals are able to slow their decent by spreading out – flying squirrel style. Simply put, animals with these characteristics are fluffy and have a high drag coefficient giving them a greater chance of surviving these falls.

ANSWER 2: (Moment of inertia is important . . .)

To understand how a cat can land on it's feet, you must first understand some concepts of rotational motion, since the cat rotates as it falls.

Rotational motion is similar to motion in a straight line (linear motion), however the constants are slightly different. For example, instead of the mass of an object, we use what is known as the moment of inertia.

The moment of inertia of an object is determined by the distance it's mass is distributed from the rotational axis. Think of a ball tied to a string that you swing around your head, the greater the length of the string, the greater the object's moment of inertia. Relating this to the cat, if the cat stretches out it's legs and tail, it increases it's moment of inertia; conversely, it can decrease it's moment of inertia by curling up. You can prove this by extending your arms while spinning around on a swivel chair.

Just as a more massive object requires more force to move, an object with a greater moment of inertia requires more torque (which is the angular equivalent of force, and is proportional to the distance from the axis of rotation) to spin. Therefore by manipulating it's moment of inertia, by extending and retracting its legs and rotating its tail, the cat can change the speed at which it rotates, giving it control over which part of it's body comes in contact with the ground.

ANSWER 3: (. . . and the conservation of angular momentum . . .)

If a cat is dropped they almost always tend to land on their feet because they use the conservation of angular momentum to change their orientation. When a cat falls, as you would expect, its centre of mass follows a parabolic path. The cat falls with a definite angular momentum about an axis through the cat’s centre of mass. When the cat is in the air, no net external torque acts on it about its centre of mass, so the angular momentum about the cats centre of mass cannot change. By pulling in its legs, the cat can considerably reduce it rotational inertia about the same axis and thus considerably increase its angular speed. Stretching out its legs increases its rotational inertia and thus slows the cat’s angular speed. The conservation of angular momentum allows the cat to rotate its body and slow its rate of rotation enough so that it lands on its feet safely.


TOPICS: Miscellaneous; Science; Weird Stuff
KEYWORDS: cat; catrotation; fallingcat; inertia; momentum
And the fun picture:


1 posted on 01/24/2005 10:53:23 AM PST by FoxInSocks
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To: FoxInSocks
Animal experts say that this instinct is observable in kittens as young as three to four weeks, and is fully developed by the age of seven weeks.

Animal experts learned this by dropping baby kittens :-)

2 posted on 01/24/2005 10:55:24 AM PST by xm177e2 (Stalinists, Maoists, Ba'athists, Pacifists: Why are they always on the same side?)
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To: FoxInSocks
Cave paintings show this principle has been understood for millenia...


3 posted on 01/24/2005 10:57:45 AM PST by Tijeras_Slim
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To: FoxInSocks

My dad used to call this "The Official Cat Trick".


4 posted on 01/24/2005 10:58:03 AM PST by stayathomemom
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To: FoxInSocks

Just another unique power in the Viking Kitty arsenel.


5 posted on 01/24/2005 10:59:28 AM PST by JennysCool (Rest in Peace, Great Carsoni!)
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To: Tijeras_Slim

Here's a point to ponder. If a buttered piece of bread lands buttered-side down more times than not, and a thrown cat lands almost always on their feet, what would happen if you affixed a piece of buttered bread on the back of a thrown cat?


6 posted on 01/24/2005 11:05:44 AM PST by NCC-1701 (ISLAM IS A CULT, PURE AND SIMPLE!!!!! IT MUST BE ERADICATED FROM THE FACE OF THE EARTH.)
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To: NCC-1701

I don't know but lets put a pancake on its head and see what happens.


7 posted on 01/24/2005 11:06:56 AM PST by DYngbld (I've read the back of the Book and guess what? .... We WIN!)
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To: xm177e2

I wonder what kind of "research" they did to determine how they survive falls from several stories? :)


8 posted on 01/24/2005 11:08:06 AM PST by rwfromkansas ("War is an ugly thing, but...the decayed feeling...which thinks nothing worth war, is worse." -Mill)
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To: NCC-1701
"Here's a point to ponder. If a buttered piece of bread lands buttered-side down more times than not, and a thrown cat lands almost always on their feet, what would happen if you affixed a piece of buttered bread on the back of a thrown cat?"

A ten penny nail works great to attach the bread.
9 posted on 01/24/2005 11:08:25 AM PST by HuntsvilleTxVeteran (So I talk to myself, at least I am talking to a mind that is my equal)
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To: DYngbld
Well, here is one that is somewhat close.


10 posted on 01/24/2005 11:09:27 AM PST by rwfromkansas ("War is an ugly thing, but...the decayed feeling...which thinks nothing worth war, is worse." -Mill)
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To: xm177e2

That was my first thought after read that line. Then I started to laugh. I am sick :)


11 posted on 01/24/2005 11:09:49 AM PST by CollegeRepublican
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To: FoxInSocks

all that without a degree from mit!


12 posted on 01/24/2005 11:10:04 AM PST by NoClones
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To: HuntsvilleTxVeteran

I like your way of thinking.


13 posted on 01/24/2005 11:10:45 AM PST by NCC-1701 (ISLAM IS A CULT, PURE AND SIMPLE!!!!! IT MUST BE ERADICATED FROM THE FACE OF THE EARTH.)
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To: NCC-1701

http://www.google.com/search?q=cat+toast+perpetual+motion


14 posted on 01/24/2005 11:11:22 AM PST by ScottFromSpokane (http://drunkengop.blogspot.com/)
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To: rwfromkansas

I wonder if you dropped a bunny if it would land on its feet.


15 posted on 01/24/2005 11:12:17 AM PST by DYngbld (I've read the back of the Book and guess what? .... We WIN!)
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To: FoxInSocks

They use their tail to flip themselves into landing position.

NEXT QUESTION...


16 posted on 01/24/2005 11:12:30 AM PST by A CA Guy (God Bless America, God bless and keep safe our fighting men and women.)
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To: NCC-1701

Depends on the price of the carpet.


17 posted on 01/24/2005 11:13:00 AM PST by Roccus (Quando Omni Flunkus Moritati)
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To: xm177e2

"OK, hand me one of the one-week-old litter....Nope. Two-week old....Nope. Three-week-old....Hey, that one worked!

"OK, get the cleaning lady in here."


18 posted on 01/24/2005 11:13:16 AM PST by ScottFromSpokane (http://drunkengop.blogspot.com/)
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To: FoxInSocks

Cats ALWAYS 'jump'!


19 posted on 01/24/2005 11:13:59 AM PST by maestro
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To: A CA Guy

So a cat without a tail will not land on its feet?
I wonder if I could get a grant to study this. I have two Cats.


20 posted on 01/24/2005 11:14:55 AM PST by DYngbld (I've read the back of the Book and guess what? .... We WIN!)
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To: DYngbld

I doubt it....lol. I have been itching to use that picture on a forum somewhere, so I took this opp....


21 posted on 01/24/2005 11:15:23 AM PST by rwfromkansas ("War is an ugly thing, but...the decayed feeling...which thinks nothing worth war, is worse." -Mill)
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To: DYngbld

A cat with no tail would have far more difficulty making the turn compared to a whole cat...YES!


22 posted on 01/24/2005 11:17:03 AM PST by A CA Guy (God Bless America, God bless and keep safe our fighting men and women.)
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To: rwfromkansas

That one's just math. Falling cats aren't very aerodynamic, and tend to be light. Because of this their terminal velocity is pretty low and reached very quickly. For anything falling once you're to terminal velocity the rest of the fall is just for show. Lots of small light animals (frogs and mice I know) can survive their own terminal velocity and could therefore, in theory, fall from any height without getting killed. Humans, on the other hand, are not among the lucky few.


23 posted on 01/24/2005 11:19:47 AM PST by discostu (mime is money)
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To: DYngbld
So a cat without a tail will not land on its feet?
I wonder if I could get a grant to study this. I have two Cats.

If you get that grant, I feel sorry for your cats!

;-)

24 posted on 01/24/2005 11:24:40 AM PST by Michael Barnes
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To: FoxInSocks

25 posted on 01/24/2005 11:26:19 AM PST by EggsAckley
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To: NCC-1701
LOL!


26 posted on 01/24/2005 11:28:36 AM PST by MotleyGirl70
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To: xm177e2

We tested my cat many times. We wondered if flinging her would make a difference. Good thing she had nine lives.


27 posted on 01/24/2005 11:30:06 AM PST by Sacajaweau (God Bless Our Troops!!)
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To: FoxInSocks
This ability is attributed to two significant feline characteristics: A “righting reflex” and a unique skeletal structure.

Except for that one kitten caught on videotape who, when swung upside down at the ceiling, always, without fail, latches on to the wooden beam with all four claws, staying suspended in the air.

How does it know not to turn himself over?

28 posted on 01/24/2005 11:31:13 AM PST by Publius6961 (The most abundant things in the universe are hydrogen, ignorance and stupidity.)
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To: Michael Barnes

I wounder if I mistook Koter as a bag of Popcorn if he would pop. JUST KIDDING!!
29 posted on 01/24/2005 11:34:05 AM PST by DYngbld (I've read the back of the Book and guess what? .... We WIN!)
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To: FoxInSocks
Cat and fan movie.
30 posted on 01/24/2005 11:37:45 AM PST by red-dawg
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To: JennysCool
"Just another unique power in the Viking Kitty arsenel"

Souplesse oblige (paraphrasing "Noblesse oblige")

31 posted on 01/24/2005 11:54:10 AM PST by Marguerite
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To: CollegeRepublican
That was my first thought after read that line. Then I started to laugh. I am sick :)

Wrong. You are only mentally ill if few other people share your bad thoughts/behavior. Since there are a lot of us on FR who reacted the same way, you are "normal enough" for society. Twisted, maybe, but not "sick."

32 posted on 01/24/2005 12:24:07 PM PST by xm177e2 (Stalinists, Maoists, Ba'athists, Pacifists: Why are they always on the same side?)
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To: red-dawg

Hilarious video. Thanks!


33 posted on 01/24/2005 12:51:35 PM PST by FoxInSocks
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To: FoxInSocks

It's no problem at all when the cat is sober...


34 posted on 01/24/2005 2:04:11 PM PST by FDNYRHEROES (Make welfare as hard to get as a building permit)
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To: FoxInSocks
My question is how do you remove the invisible Velcro from your legs and the cat's body to avoid crushing the cat's spine or breaking your own legs in the inevitable fall?
35 posted on 01/24/2005 2:45:22 PM PST by SilentServiceCPOWife (Schni schna schnappi, schnappi, schnappi, schnapp!)
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To: FoxInSocks

I really don't know the answer to the question!

36 posted on 01/31/2005 6:33:09 AM PST by Soaring Feather
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To: FoxInSocks

37 posted on 01/31/2005 6:47:37 AM PST by Sloth (Al Franken is a racist.)
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To: NCC-1701

a stephen wright bump.....I love that joke.


38 posted on 01/31/2005 6:49:27 AM PST by gortklattu (As the preacher in Blazing Saddles said "You're on your own.")
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To: Sloth

That's an interesting graph. I wonder why the injuries drop off after the eighth floor.


39 posted on 01/31/2005 12:17:22 PM PST by FoxInSocks
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To: FoxInSocks

As I understand it, it takes the cats that long to twist their bodies around to their optimum falling position -- if they hit the ground before that, they may be in a position that promotes greater injury.


40 posted on 01/31/2005 12:20:57 PM PST by Sloth (Al Franken is a racist.)
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To: Sloth

That's a logical explanation. I suppose I could dig up my old physics textbook and figure out how long that is in seconds . . .


41 posted on 01/31/2005 1:03:43 PM PST by FoxInSocks
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