# 199: Right-Hand Rule

Right-Hand Rule |

Title text: To really expand your mind try some noncartesian porn. Edwin Abbot Abbott has nothing on "Girls on Girls in Tightly Closed Nonorientable Spaces" |

## Explanation

The right-hand rule is a mathematics and physics trick to learning how to find the cross product of two Cartesian vectors in three dimensions. First, position your right arm in the direction of the first vector (in the example diagram in the comic, this is to the left). Then, curl your fingers in the direction of the second vector (out of the page/screen, in the example). Now point your thumb perpendicular to the other fingers, and it will point in the direction of the cross product of those two vectors (upwards, in the example). Note that reversing the order of the two vectors also reverses the direction of the cross product.

The joke relies on non-standard ways of measuring, which are unusual and much more impractical. To emphasize this, the third method only works for males, provided that he is not impotent, while looking at porn.

The title text refers to Edwin Abbott Abbott, author of the book Flatland, a story about a two dimensional world.

## Transcript

- [Picture of a right hand with fingers curved, thumb pointed away, with axes drawn to demonstrate the right-hand rule of physics.]
- Alternatives to the Right-Hand Rule in vector multiplication:
- [A slightly-open book with labeled axes drawn on.]
- Book Rule: Open the front cover along the first vector and the back cover along the second. The result vector is along the spine, out the top.
- [A handgun with axes.]
- Handgun Rule: Point the grip along the first vector and rotate it so that the second vector is on the safety latch side. Fire. The result vector is toward the nozzle.
- [A person with right arm extended.]
- Body Rule (males only): Point your right arm along the first vector and your legs along the second, then watch some porn.

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# Discussion

There's also the right hand rule on urban dictionary, although it's applied slightly differently, and it only has one input parameter. Davidy22 (talk) 03:44, 30 October 2012 (UTC)

I expanded the explanation to cover the erection joke. 184.66.160.91 02:12, 27 August 2013 (UTC)