HaHa I just had to look up the date [April 20] ... too soon to change my profile pic. Thanks for the promote

>> ^BoneRemake:

"Euler's Disk" is a trademark for a product manufactured and distributed by the "Damert Company" (Toysmith Group), consisting of a metal disk, a base having an upwards-facing concave mirror, and holographic, patterned magnetic stickers. One or more magnetic stickers may be attached to the top surface of the disk. The disk, when spun on the mirror, exhibits a spinning/rolling motion. Euler’s Disk has an optimized aspect ratio and precision polished, rounded edges to maximize the spinning/rolling time. A coin spun on a table, or any disc spun on a relatively flat surface, exhibits essentially the same type of motion.
A spinning/rolling disk ultimately comes to rest; and it does so quite abruptly, the final stage of motion being accompanied by a whirring sound of rapidly increasing frequency. As the disk rolls, the point P of rolling contact describes a circle that oscillates with a constant angular velocity ω. If the motion is non-dissipative, ω is constant and the motion persists forever, contrary to observation (since ω is not constant in real life situations).
In the April 20, 2000 edition of Nature, Keith Moffatt shows that viscous dissipation in the thin layer of air between the disk and the table is sufficient to account for the observed abruptness of the settling process. He also showed that the motion concluded in a finite-time singularity.
Moffatt shows that, as time t approaches a particular time t0 (which is mathematically a constant of integration), the viscous dissipation approaches infinity. The singularity that this implies is not realized in practice because the vertical acceleration cannot exceed the acceleration due to gravity in magnitude. Moffatt goes on to show that the theory breaks down at a time τ before the final settling time t0, given by
\tau\simeq\left(2a/9g\right)^{3/5} \left(2\pi\mu a/M\right)^{1/5}
where a is the radius of the disk, g is the acceleration due to Earth's gravity, μ the dynamic viscosity of air, and M the mass of the disk. For the commercial toy (see link below), τ is about 10 − 2 seconds, at which \alpha\simeq 0.005 and the rolling angular velocity \Omega\simeq 500\rm Hz.
Using the above notation, the total spinning time is
t_0=\left(\frac{\alpha_0^3}{2\pi}\right)\frac{M}{\mu a}
where α0 is the initial inclination of the disk. Moffatt also showed that, if t0 − t > τ, the finite-time singularity in Ω is given by.....
http://en.wikipedia.org/wiki/Euler%27s_disk


Nerd.

"Euler's Disk" is a trademark for a product manufactured and distributed by the "Damert Company" (Toysmith Group), consisting of a metal disk, a base having an upwards-facing concave mirror, and holographic, patterned magnetic stickers. One or more magnetic stickers may be attached to the top surface of the disk. The disk, when spun on the mirror, exhibits a spinning/rolling motion. Euler’s Disk has an optimized aspect ratio and precision polished, rounded edges to maximize the spinning/rolling time. A coin spun on a table, or any disc spun on a relatively flat surface, exhibits essentially the same type of motion.

A spinning/rolling disk ultimately comes to rest; and it does so quite abruptly, the final stage of motion being accompanied by a whirring sound of rapidly increasing frequency. As the disk rolls, the point P of rolling contact describes a circle that oscillates with a constant angular velocity ω. If the motion is non-dissipative, ω is constant and the motion persists forever, contrary to observation (since ω is not constant in real life situations).

In the April 20, 2000 edition of Nature, Keith Moffatt shows that viscous dissipation in the thin layer of air between the disk and the table is sufficient to account for the observed abruptness of the settling process. He also showed that the motion concluded in a finite-time singularity.

Moffatt shows that, as time t approaches a particular time t0 (which is mathematically a constant of integration), the viscous dissipation approaches infinity. The singularity that this implies is not realized in practice because the vertical acceleration cannot exceed the acceleration due to gravity in magnitude. Moffatt goes on to show that the theory breaks down at a time τ before the final settling time t0, given by

\tau\simeq\left(2a/9g\right)^{3/5} \left(2\pi\mu a/M\right)^{1/5}

where a is the radius of the disk, g is the acceleration due to Earth's gravity, μ the dynamic viscosity of air, and M the mass of the disk. For the commercial toy (see link below), τ is about 10 − 2 seconds, at which \alpha\simeq 0.005 and the rolling angular velocity \Omega\simeq 500\rm Hz.

Using the above notation, the total spinning time is

t_0=\left(\frac{\alpha_0^3}{2\pi}\right)\frac{M}{\mu a}

where α0 is the initial inclination of the disk. Moffatt also showed that, if t0 − t > τ, the finite-time singularity in Ω is given by.....

http://en.wikipedia.org/wiki/Euler%27s_disk

for the Canucks:
http://watch.thecomedynetwork.ca/the-daily-show-with-jon-stewart/full-episodes/the-daily-show-with-jon-stewart---april-20-2010/#clip290964

Still, holds no candle compared to this:
http://en.wikipedia.org/wiki/File:Gypsy_Van_Front.jpg

Gypsy home built in 1968 on a 1937 GMC F-16 Chassis. The framework is oak, and the interior is handcrafted in fine woods and leather with antique furniture. It can sleep six (a double bed is located in a loft beneath the dome visible above the cab), and it has a full-sized stove, a sink, a shower, hot and cold running water, a coal burning stove, a living/dining area and a back porch.

Originally named "Leviathan," the truck was present on the first day of building People's Park, April 20, 1969. It was also driven, with friends, to a Spring, 1969 love-in on the top of Mount Tamalpais near San Francisco.

I'm sorry gorillaman, but I respectfully disagree: intention is mostly irrelevant. If someone bonks you on the head with a tennis racket while you were just standing there minding your own business, is it important whether the person who bonked you did it because you were of a certain racial background or because he simply didn't like your yellow shirt? The crime is the bonk, not the intent behind it.


A little history lesson for the woefully ignorant on the origins of hate crimes:

During 1988, the predominant architect of “Anti-Hate” legislation, the Jewish Anti-Defamation League of B’nai B’rith, helped sponsor a nationwide, law-student competition to write a model “Anti-Hate” law for America. This law would criminalize not just physical acts of racial violence but statements that might lead to violence.

On April 20-22, the ADL helped sponsor a conference at New York’s prestigious Hofstra University entitled “Group Defamation and Freedom of Speech: The Relationship Between Language and Violence.” Rep. John Conyers, Jr. (D-Mich), also a pioneer of the hate crimes legislation now before Congress, was the keynote speaker. The winner of the hate crimes competition was announced as Joseph Ribakoff, a law student from Whittier College in California.

In his prize-winning proposal, Ribakoff asserted that with the upsurge of “Hate Crimes” in America, it will no longer suffice for the government merely to outlaw acts of physical violence; it must ban those forms of verbal communication which cause hatred, suspicion, and possible violence against groups of people. Ribakoff recommends that federal and state censorship boards be established to review all films and videotapes before they are shown publicly, determining if they contain statements which might stimulate hatred or contempt for some group of people. If so, an immediate court order would ban the film in America. Ribakoff: “Any person, persons, or organizations which publicly shows a film or movie before it has been submitted and reviewed by the agency shall have committed a misdemeanor.”

Further, if anyone is a member of an organization that has publicly shown such a film and intends to remain a member, supportive of its goals, he also will have committed a misdemeanor.

Ribakoff’s prize-winning “Group Libel Statute” was not limited to verbal criticism of Blacks, Jews, Hispanics, etc., but would indict anyone who criticized homosexuals as a group, causing “mental anguish” to members of that minority.

And so it began. Other countries are far deeper into this Orwellian nightmare than the USA.

Preachers in Canada and Europe can now be jailed for preaching the Bible's condemnation of homosexuality.

Whether you agree with the Bible or not, that's far scarier than the boogeyman liberals are trying to make out of the Patriot Act.

Edith Minturn "Edie" Sedgwick (April 20, 1943 – November 15, 1971) was an American actress, socialite, debutante and heiress who starred in many of Andy Warhol's short films in the 1960s.

http://en.wikipedia.org/wiki/Edie_Sedgwick

This video includes many clips from the Leonardo DiCaprio movie, "Basketball Diaries."

If you watch closely, you'll see a few seconds of a controversial scene mentioned in the Wikipedia article about the movie:

"Controversy arose again in the wake of the Columbine High School massacre on April 20, 1999. The film contains a dream sequence in which Jim enters his school while wearing a black trenchcoat and shoots several students and teachers with a shotgun while his friends cheer him on."

http://en.wikipedia.org/wiki/The_Basketball_Diaries_%28film%29

Farhad - not sure if you've noticed...but my favourite Sift is "Grass" - History of Marijuana Documentary, and I posted this (IE: I'm well experienced in the ways of 'weed'). Yet, I have never heard of '420' - and sorry to say, but the wiki's "Cannabis users gather on April 20 ("4/20" in U.S. dating shorthand) every year to celebrate and consume marijuana. 4:20p.m. (or even a.m.) is also a popular time to consume cannabis." is a little incredulous to me (yeah - I'm going for obscure words now!) But I guess we have a different cannabis culture in the UK to the rest of the world...