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Professor Interface's Essays: Analysis of Cartoon Physics
Issue 3: Flattening

"Flattening" is the term for when due to cartoon physics or abnormal physical properties, a character is subjected to compressional forces and harmlessly pressed thin instead of injured.  Although cartoon physics is subjective by its very nature, I will try to cover the basic trends and things that make them common.

Compressional Forces?
Yes, that's what I said... oh, I forgot.  Not all of you are physics majors.  No matter, I'll explain.

Compressional forces are when two "pushing" forces act on a subject from different directions, such as the pressure of a heavy weight falling from the sky and the supporting force of the ground below.

Of course, this is in contrast with tensional forces, which are still in opposite directions but pulling instead of pushing.  If you were to chain someone's ankles to a wall and then pull really hard on their arms, your pull and the tension of the chains would be an example of tensional forces.  (I'll get back to that on Issue 5 "Elasticity".)

Remember: a pushing force acts away from the direction it's coming from, and a pulling force acts towards the direction it's coming from.

Two types of flattening
There are two basic types of flattening: normal flattening and disk flattening.  Which one is applicable depends on the direction of compression and the orientation of the subject at the time.

To determine the type you need, you first need to plot two lines in three-dimensional space: the force line and the orientation line.  The force line is parallel to the direction of the compressional forces; for example, in the heavy object/ground example noted above, the force line would be vertical.  A good rule of thumb to remember is that if a subject is flattened against a stationary surface, such as the ground, the force line will always be perpendicular to that surface.

The orientation line is parallel to a rough estimation of the character's spine at the exact moment of the flattening; for example, if they were standing up the orientation line will be vertical.

The type of flattening is determined by the relationship between the force and orientation lines.  If the lines are roughly perpendicular, a normal flattening occurs; if they are roughly parallel, a disk flattening occurs.

Be very careful when plotting these lines, as some situations can be complicated.  Try to picture the situation in slow motion.  For example, if a person is flattened by a steamroller, the roller will most likely knock the subject over before crushing them, which means they'll be lying down during the flattening, and the orientation line will be horizontal.  Because the subject is pressed against the ground by the roller, the force line will be vertical.

Normal Flattening
As noted above, normal flattening occurs when a subject is flattened with a force perpendicular to their orientation (for example, run lengthwise through a laundry wringer).  Typically the subject will appear no different when viewed from a direction perpendicular to the force line, having had their outline preserved perfectly.

Although there are exceptions, the majority of the displaced mass typically disappears entirely until the flattening is undone.  This apparent violation of the law of conservation of mass is a prime example of the "Coyote effect", the effect that allows cartoon physics to undermine all other branches of physics and science whenever appropriate.

Disk Flattening
Disk flattening takes place when a subject is flattened parallel to their orientation (for example, crushed by a falling object while standing upright).  As the name implies, the subject is compacted into a circular disk by the compressional forces.  Often the subject's face will decorate the front of the disk, not unusual because a common instinct when one is about to be crushed by something is to look up at it.

This occurs instead of normal flattening because the ratios of the subject's bodily dimensions mean a significantly higher percentage of displaced mass, so it spreads out radially instead of disappearing.  The Coyote effect noted above is weaker with disk flattening than with normal flattening, but still prevalent.

Final Observations
There are many other details to consider about flattening, but they are typically much less constant than those discussed above.  Such details include how rigid the flattened subject is, their ability to move or speak when flattened, and how easily the flattening can be undone.  (For the last one, sometimes the subject will "pop" back to normal by themselves after a moment, but sometimes they'll have to be restored via external stimuli such as inflation or exposure to steam or hot water.)  As there is no clear precedent to them, I shall not discuss them in detail.  As I said at the very beginning, cartoon physics is subjective by its very nature.

Always remember, do not rely on cartoon physics to save your life unless you are absolutely certain it applies.  Get in front of a steamroller and it could very easily break every bone in your body!

Description
Professor Interface's Essays: Analysis of Cartoon Physics
Issue 3: Flattening

"Flattening" is the term for when due to cartoon physics or abnormal physical properties, a character is subjected to compressional forces and harmlessly pressed thin instead of injured.  Although cartoon physics is subjective by its very nature, I will try to cover the basic trends and things that make them common.

Compressional Forces?
Yes, that's what I said... oh, I forgot.  Not all of you are physics majors.  No matter, I'll explain.

Compressional forces are when two "pushing" forces act on a subject from different directions, such as the pressure of a heavy weight falling from the sky and the supporting force of the ground below.

Of course, this is in contrast with tensional forces, which are still in opposite directions but pulling instead of pushing.  If you were to chain someone's ankles to a wall and then pull really hard on their arms, your pull and the tension of the chains would be an example of tensional forces.  (I'll get back to that on Issue 5 "Elasticity".)

Remember: a pushing force acts away from the direction it's coming from, and a pulling force acts towards the direction it's coming from.

Two types of flattening
There are two basic types of flattening: normal flattening and disk flattening.  Which one is applicable depends on the direction of compression and the orientation of the subject at the time.

To determine the type you need, you first need to plot two lines in three-dimensional space: the force line and the orientation line.  The force line is parallel to the direction of the compressional forces; for example, in the heavy object/ground example noted above, the force line would be vertical.  A good rule of thumb to remember is that if a subject is flattened against a stationary surface, such as the ground, the force line will always be perpendicular to that surface.

The orientation line is parallel to a rough estimation of the character's spine at the exact moment of the flattening; for example, if they were standing up the orientation line will be vertical.

The type of flattening is determined by the relationship between the force and orientation lines.  If the lines are roughly perpendicular, a normal flattening occurs; if they are roughly parallel, a disk flattening occurs.

Be very careful when plotting these lines, as some situations can be complicated.  Try to picture the situation in slow motion.  For example, if a person is flattened by a steamroller, the roller will most likely knock the subject over before crushing them, which means they'll be lying down during the flattening, and the orientation line will be horizontal.  Because the subject is pressed against the ground by the roller, the force line will be vertical.

Normal Flattening
As noted above, normal flattening occurs when a subject is flattened with a force perpendicular to their orientation (for example, run lengthwise through a laundry wringer).  Typically the subject will appear no different when viewed from a direction perpendicular to the force line, having had their outline preserved perfectly.

Although there are exceptions, the majority of the displaced mass typically disappears entirely until the flattening is undone.  This apparent violation of the law of conservation of mass is a prime example of the "Coyote effect", the effect that allows cartoon physics to undermine all other branches of physics and science whenever appropriate.

Disk Flattening
Disk flattening takes place when a subject is flattened parallel to their orientation (for example, crushed by a falling object while standing upright).  As the name implies, the subject is compacted into a circular disk by the compressional forces.  Often the subject's face will decorate the front of the disk, not unusual because a common instinct when one is about to be crushed by something is to look up at it.

This occurs instead of normal flattening because the ratios of the subject's bodily dimensions mean a significantly higher percentage of displaced mass, so it spreads out radially instead of disappearing.  The Coyote effect noted above is weaker with disk flattening than with normal flattening, but still prevalent.

Final Observations
There are many other details to consider about flattening, but they are typically much less constant than those discussed above.  Such details include how rigid the flattened subject is, their ability to move or speak when flattened, and how easily the flattening can be undone.  (For the last one, sometimes the subject will "pop" back to normal by themselves after a moment, but sometimes they'll have to be restored via external stimuli such as inflation or exposure to steam or hot water.)  As there is no clear precedent to them, I shall not discuss them in detail.  As I said at the very beginning, cartoon physics is subjective by its very nature.

Always remember, do not rely on cartoon physics to save your life unless you are absolutely certain it applies.  Get in front of a steamroller and it could very easily break every bone in your body!