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March 30, 2003

A Different View

The reportage from the “embedded” reporters on the Iraq war is certainly compelling, if somewhat blinkered. There is — both metaphorically and physically — not much visibility from the inside of a Bradley APC.

For another perspective, check out the coverage from ArabNews.com, Saudi Arabia’s “first English Daily”. One of their reporters in particular, Essam Al-Ghalib has been in Basra and has a riveting series of dispatches from Southern Iraq: I, II, III.

Posted by distler at 9:12 PM | Permalink | Post a Comment

March 29, 2003

Sendmail 8.12.9

Sigh. And I thought I would have a quiet weekend doing my taxes.

Posted by distler at 4:28 PM | Permalink | Post a Comment

Michigan Residents: Use NAT, Go to Jail

Ed Felten points out that the State of Michigan has made it a felony to use IP Masquerading, Firewall, or VPN software.

The punishment for hooking a NAT router to your cable modem or using a VPN to connect to the LAN at work (“conceal the existence or place of origin or destination of any telecommunications service.”)? Up to 4 years in jail and a $2000 fine.

Manufacturers of DSL Routers and authors of software with these capabilities are subject to the same penalties.

Michigan residents: you have until Monday, March 31 to comply.

Other states (including my own) are considering equally mad legislation.

Posted by distler at 11:22 AM | Permalink | Followups (3)

March 28, 2003

Pity the Freshmen

I’m teaching Freshman Mechanics this semester. Not exactly the most uplifting of subjects. Still, even here, one can find surprising tidbits of beauty.

Consider a pencil (a uniform rod) balanced on its tip. As the rod begins to fall, the tip is held in place by the force of static friction exerted by the table.

  1. No matter how large the coefficient of static friction, μ, the rod will reach a critical angle, θ, at which it will begin to slide.
  2. For small μ, the tip will slide the opposite direction from the direction of fall. For large μ, the tip will slide in the same direction as the direction of fall.
  3. For very large μ, the critical angle (measured from vertical) at which the tip begins to slide is cos −1 (1 /3 )∼70.5 °
  4. There’s a critical value of μ, μ crit=15 10 128 ∼0.37 at which the behaviour changes abruptly. Below μ crit, the tip begins to slide opposite the direction of fall at a critical angle which approaches cos −1 (9 /11 )∼35.1 ° as we approach μ crit from below. Above μ crit, the tip begins to slide in the same direction as the direction of fall at a critical angle which approaches cos −1 ((48 14 −35 )/231 )∼51.2 ° as we approach μ crit