Cartoon physics

Cartoon physics or animation physics are terms for a jocular system of laws of physics (and biology) that supersedes the normal laws, used in animation for humorous effect.
Many of the most famous American animated films, particularly those from Warner Bros. and Metro-Goldwyn-Mayer studios, indirectly developed a relatively consistent set of such "laws" which have become de rigueur in comic animation. They usually involve things behaving in accordance with how they appear to the cartoon characters, or what the characters expect, rather than how they objectively are. In one common example, when a cartoon character runs off a cliff, gravity has no effect until the character notices.
In words attributed to Art Babbitt, an animator with the Walt Disney Studios: "Animation follows the laws of physics—unless it is funnier otherwise."
Examples.
Specific reference to "cartoon physics" extends back at least to June 1980, when an article "O'Donnell's Laws of Cartoon Motion" appeared in "Esquire". A version printed in V.18 No. 7 p. 12, 1994 by the Institute of Electrical and Electronics Engineers in its journal helped spread the word among the technical crowd, which has expanded and refined the idea. These laws are outlined on dozens of websites.
O'Donnell's examples include: 
History of the idea.
The idea that cartoons behave differently from the real world, but not randomly, is virtually as old as animation. Walt Disney, for example, spoke of the plausible impossible in 1956 on an episode of the "Disneyland" television program.
Warner Brothers Looney Tunes had numerous examples of their own cartoon physics (such as in the Wile E. Coyote and the Road Runner cartoons) or even acknowledged they ignore real world physics. In "High Diving Hare" (1948), when Yosemite Sam cuts through a high diving board Bugs Bunny is standing on, the ladder and platform that Sam is on falls, leaving the cut plank suspended in mid-air. Bugs turns to the camera and cracks: "I know this defies the law of gravity, but, you see, I never studied law!"
More recently, it has been explicitly described by some cartoon characters, including Roger Rabbit, Bonkers D. Bobcat, and Yakko, Wakko, and Dot, who say that toons are allowed to bend or break natural laws for the purposes of comedy. Doing this is extremely tricky, so toons have a natural sense of comedic timing, giving them inherently funny properties.
In "Who Framed Roger Rabbit", for example, Roger is unable to escape handcuffs for most of a sequence, doing so only to use both hands to hold the table still while Eddie Valiant attempts to saw the cuff off. When Eddie asks, exasperated, "Do you mean to tell me you could've taken your hand out of that cuff at any time?!" Roger responds: "Not at "any" time! Only when it was "funny"!" Several aspects of cartoon physics were discussed in the film's dialogue, and the concept was a minor plot theme.
In 1993, Stephen R. Gould, then a financial training consultant, writing in "New Scientist", said that "... these seemingly nonsensical phenomena can be described by logical laws similar to those in our world. Nonsensical events are by no means limited to the Looniverse. Laws that govern our own Universe often seem contrary to common sense." This theme is described by Alan Cholodenko in his article, "The Nutty Universe of Animation".
In a Garfield animated short entitled "Secrets of the Animated Cartoon", the characters Orson and Wade give demonstrations of different laws of the cartoons and show humorous examples of them.
In 2012 O'Donnell's Laws of Cartoon Motion were used as the basis for a presentation and exhibition by Andy Holden at Kingston University in Great Britain. Titled 'Laws of Motion in a Cartoon Landscape' it explored ideas of cartoon physics in relation to art and the end of art history. This was later made into a film with the artist as an animated cartoon character and shown at Glasgow International Festival in 2016, Tate Britain in 2017, and Future Generation Art Prize at Venice Biennale in 2017.
Non-exclusivity.
In an editorial for the "New York Times" in 2003 titled "Don't Look Down", economist Paul Krugman cited Wile E. Coyote's ability to temporarily suspend the law of gravity while describing the United States' structural gap between revenue and spending: "The crisis won't come immediately. For a few years, America will still be able to borrow freely, simply because lenders assume that things will somehow work out...But at a certain point we'll have a Wile E. Coyote moment. For those not familiar with the Road Runner cartoons, Mr. Coyote had a habit of running off cliffs and taking several steps on thin air before noticing that there was nothing underneath his feet. Only then would he plunge. What will that plunge look like?"
"Cartoon physics" is not limited to physics: For example, when a character recovers impossibly fast from a serious injury, the laws of biology rather than physics are being altered.
It is also not limited to cartoons. Live-action shows and movies can also be subject to the laws of cartoon physics explaining why, for example, The Three Stooges did not go blind from all the eye-poking, or the burglars in the "Home Alone" series survive life-threatening booby traps. In the live-action "Pete's Dragon (1977 film)", the titular Elliot, while invisible, bursts through a wooden wall, leaving a dragon-shaped "silhouette of passage".
In a review of one of the "Home Alone" films, film critic Roger Ebert noted that in the case of live-action productions, cartoon physics are not as effective at producing a comic effect, as the effects seem more realistic:
Printed cartoons have their own family of cartoon physics "laws" and conventions.
Additionally, some video games utilize these elements during their cutscenes. For example, in the game Sonic Unleashed, titular character Sonic the Hedgehog is seen making effective use of the hammerspace to stash a Chaos Emerald.