Editing 2649: Physics Cost-Saving Tips

In the title text, Randall claims to have been banned from the county fair for handing out helium-2 balloons because of the instant massive explosions caused by its radioactive decay (that helium-2 decays fast is mentioned in the comic, with a joke suggestion to use it quickly). He jokes that the balloons violated a local ordinance. {{w|Gas balloon|Helium balloons}} are often given out at county fairs and similar events, but they are filled with {{w|helium-4}} and therefore inert (a very small part will be {{w|helium-3}}, 2 ppm). A balloon filled with helium-2 is a practical impossibility because of its nanosecond half-life. Assuming a 12-inch diameter balloon at 1 atmosphere of pressure, the balloon-bomb would have a yield of roughly 17 {{w|TNT equivalent|tons of TNT equivalent}}.

The smallest nuclear bomb, the {{w|W54}}, had a yield of between 10 and 1,000 tons of TNT. The largest conventional bomb, the {{w|GBU-43/B MOAB}}, has a yield of roughly 11 tons. The {{w|2020 Beirut explosion}} was roughly equivalent to 500 tons. So, while the helium-2 balloon bomb would be larger than all conventional bombs, it would still be smaller than most nukes. Handing out what are effectively small atomic bombs at a county fair would not go down well with any surviving local authorities,{{Citation needed}} so merely being banned is a very mild punishment. Criminal charges such as mass murder and terrorism would be more likely if it weren't for the absurd impossibility of the scenario.

 

The title text is likely also a pun, as the word "{{w|Local ordinance|ordinance}}" means a local law, and the very similar sounding word "[https://www.merriam-webster.com/dictionary/ordnance ordnance]" means artillery and other explosive weapons, which the balloon would qualify as.

|[[File:Torque animation.gif|frame|right|Relationship of pseudovectors {{w|torque}} ('''τ''') and {{w|angular momentum}} ('''L''') to "regular" Euclidean vectors {{w|Position (vector)|position}} ('''r'''), {{w|force}} ('''F'''), and linear {{w|momentum}} ('''p''') in an oscillatory rotating system. Not shown is the {{w|centripetal force}} of the spoke's {{w|Tension (physics)|tension}}, a Euclidean vector towards the axle proportional to linear momentum, converting it to angular momentum.]]

The prefix "pseudo-" refers to an inauthentic variation of something. Fakes are usually cheaper than their original brand-name product, while often working just as well, so the comic implies a {{w|pseudovector}} could be a less expensive substitute for a regular vector. On the contrary, pseudovectors, or axial vectors, are distinct from regular {{w|Euclidean vector}}s, which have a magnitude and direction (velocity, for example). Pseudovectors are usually being involved with rotation or physical effects that share properties with rotation, similar to the relationship between angles and lengths. Pseudovectors are formed from the {{w|cross product}}s of Euclidean vectors, in three dimensions, and while similar to Euclidean vectors, there is no physical meaning to their specific direction, only their magnitude and portions of their position. For example, {{w|angular momentum}} is described by a pseudovector, labeled '''L''' in the comic, {{w|Normal (geometry)|normal}} to the {{w|plane of rotation}}, originating from the center of rotation, with magnitude equal to the angular velocity of rotation '''ω''' multiplied by the {{w|moment of inertia}} '''I'''. (The comic's diagram is drawn according to very uncommon {{w|Right-hand rule#Coordinates|left-handed coordinates}} instead of the standard {{w|right-hand rule}}. Randall is right-handed.[https://www.youtube.com/watch?v=j1tcyEo2tQk&t=28s])

|{{w|Fourier analysis}} can decompose any periodic function into a series of {{w|sine wave}}s. A {{w|square wave}} is equal to the sum of an infinite series of sine waves. However, the sine waves are not removed or separated individually, so such a {{w|Fourier transform}} does not produce a "supply" of sine waves for practical use in any tasks other than analysis, and as abstract mathematical objects are exempt from the laws of supply and demand ({{w|File:Munitions_T-shirt_(front).jpg|most of the time}}),

|{{w|Charge carrier|Free}} {{w|electron}}s are electrons that are not tightly bound to specific atoms so [https://www.youtube.com/watch?v=TGUteH93xNo they can move freely,] such as in {{w|conduction band}}s of the {{w|metallic bond}}s throughout the iron ingot depicted in the comic. Randall interprets "free" in a different sense, meaning no cost. The charges free electrons carry are electric, not monetary as implied by the pun. Ordinary matter usually contains electrons, but although the {{w|dielectric}} layer of a {{w|capacitor}} can collect electrons, it is not easy to store pure electrons, as they repel each other. When a {{w|Solution (chemistry)|solution}} has free electrons, it becomes {{w|alkaline}} ({{w|Base (chemistry)|basic}}) and corrosive. Randall has [https://what-if.xkcd.com/140/ explained the problems] with collecting a large number of electrons before.