This is not what all the talking heads are saying, but I’m almost positive this would be the end result of this mental exercise. For the uninitiated, look at BoingBoing:

David Pogue at the NYT has presented this classic airplane on a giant treadmill problem, and people are arguing about whether or not the plane would take off or not. Here’s the problem:

“Imagine a plane is sitting on a massive conveyor belt, as wide and as long as a runway. The conveyer belt is designed to exactly match the speed of the wheels, moving in the opposite direction. Can the plane take off? “I say no, because the plane will not move relative the the ground and air, and thus, very little air will flow over the wings. However, other people are convinced that since the wheels of a plane are free spinning, and not powered by the engines, and the engines provide thrust against the air, that somehow that makes a difference and air will flow over the wing.”

I say yes. Let’s assume the friction in the wheel bearings is negligible. Putting a plane on a treadmill is like putting it on an icy lake. When you fire up the jets, the plane is going to shoot down the lake and take off just like it would on a runway.

The most important issue is that even if the the friction is negligiblein most situations, it does exist. Therefore it is important in this case. The detail being missed by most people is the way the question is set up: the treadmill is set to match the speed of the wheels, not the land speed (actual or normal) of the aircraft. So, in order to answer this question you have to get technical. Let us assume that there is enough tread on the wheels so that the friction of the wheels does matter (meaning that when the plane goes forward, the wheels move with it). This is to defeat the “icy lake” hypothesis which is based on the fact that one an icy lake, the wheels don’t turn at the land speed, mainly because the plane is in effect in a long slide. Here’s the solution:

1. The engines start up creating a forward force in the upper half of the plane body, because the land speed is not yet big enough to create lift and the engines are parallel to the ground, this force pushes down onto the wheels with the help of our friend gravity.
2. The wheels move as the plane’s body begins to be acted upon that force.
3. The treadmill matched the speed of the wheels movement, creating a backwards force that initially matches the forward force.
4. 2 and 3 get into a bit of a Cold War era armament situation: because the forward force is not generated by the wheels, the wheels spin free, meaning their speed is increased beyond what it would take in a standard situation to take off. The treadmill speed matches the wheel speed. Now, remember that in order for the plane to move forward and the wheels to meet the friction needed in the axiom (because the treadmill is a surface that would give traction, there is friction) the wheels would need to spin faster than the treadmill for forward momentum. Therefore the backward force generated by the treadmill would get significantly higher. So rinse and repeat until 5.
5. The treadmill is designed (by nature of the problem) to be able to handle infinitely high speeds. The wheels, being true physical objects have a failure speed. The wheels fail, the plane makes physical contact with the treadmill, and is thrown back into the airport. Everyone dies.

The end result before death would be the forward force remaining relatively constant and the backward force being several orders of magnitude stronger. Which of course would beg the question, why don’t we use this magical treadmill to launch these planes into the air. If it generates so much force, short flights wouldn’t even need engines…

EDIT:  I suppose that I should directly address Mark’s point.  The wheels in a normal situation act as the icy lake, they remove the friction from the ground for the plane as a whole.  What happens with the treadmill, is that by moving at would be around an infinite speed (hence the implausibility of this problem)  it would in fact create a whole lot of friction for the plane, making it the exact opposite of the frozen lake.  Oh and before anyone attacks my idea as overly simplistic, I forgot to give a few assumptions:

• 1-5 occur almost instantly.
• The wheels won’t slip.  If they do, the plane will take off or a wheel will blow, killing everyone.  If it takes off, I wouldn’t want to be on the plane.  We still need that wheel when we land.
• If you ignore the practical limits of airplanes, this question becomes totally meaningless, as both the wheel and the treadmill will have broken the speed of light and saved Lois Lane from an earthquake.  Therefore, they both heroes and should be left alone for their retirement.
• Either the tire will blow or the bearings will break: the plane will never take off, only crash and be flung back into the airport.

As per Om Malik and The Apple Blog, the record companies are again trying to claim that if we own an iPod (or Zune, or whatever), we are simply theives (billboard.com). To this end, I think we should state approximately how much legal music we have on our iPods (Zunes/Rios/whatevers). That way, even a quick Google search will prove just how wrong these asshats are.

For me personally, that number is is 3800 songs at about 20 GB of data. This music was either purchased at iTMS, ripped from a CD that I own, or offered online by the artist for free.

Generally here I speak of web design and development, but I do have other roles that I have played.  Today, I want to speak as a Systems Administrator and talk about security.

Security on a network level is based on a number of different factors, most of which are addressable any sort of systems group.  These include patches, firewalls, open ports, password policies, etc.  Generally the weakest link in network security is the rules.

A sysadmin must walk a fine line between enabling users to work as unencumbered as they wish and to protect the users from themselves.  For this reason, best practices must be put into place.  Hopefully an organization will also codify officially these rules so that everyone knows the playing field.

A major rule that I have always had is one in which remote access is minimized.  In fact, I call this rule “No Remote Access.”  Remote access allows for a user to (surprise) remotely access network resources (shared files on a server, etc.).  This means that I, as sysadmin, lose control of the client machines.  I can no longer verify that they are virus free, that they haven’t been stolen with all the passwords and addresses saved or written down.  In short, the portions of the network that the user has access to are compromised in such a way that I have no idea what is legitimate or not.

By enabling remote access in an organization, you are in fact greatly increasing the chance of downtime due to virus or lost data.  Does that seem smart?

It’s good to see that my website does handle IE7 fine.  Aside from that, I should post a bit of an update.  In the past two months, I got a new job and moved up to Boston.  i will be strating everything back up again soon, in case you are still waiting patiently.  (If so, thanks)

In my new job, I am blessed (HA) with a Windows development box.  This has been awhile for me.  I thinks that it has been five years since I have done web development on a Windows machine.  The world has changed a bit since I left; I’m just trying to figure out how.

For development, I have been working with Dreamweaver (pretty much the same as five years ago, except that I now strictly use code view).  Photoshop is the same throughout. 

In a month, I have lost at least two days of total time to Windows Update and AV updates.  The OS is still slow and feels cludgy (more so than Linux even).  I come home at night and enjoy simple acts of checking mail and surfing the web on the Mac.

Being on the OS does allow me to try out some of the new toys (reviews of which are forth coming).  I am actually writing this on Windows Live Writer and it actually seems to be fairly intuitive.  Here’s to a brave new world.

This moment is the one I have feared for months: IE7 is here. Along with this momentous day comes the possible breaking of a great many sites.

If you haven’t figured this out about me yet, well, I’ll just tell you. I see the worst possible end result constantly, and, in this case, my Powerbook is of no use in determining if I have reason to be frightened. I have heard good things about the betas, but I do understand that the rendering engine, while much better, has some different behaviors when playing with compliant sites. If you are a Windows user who has upgraded, please let me know if anything isn’t working with my site…

Well, Sploid is gone. Judging from the lack of comment from most of the blogosphere, this is a loss that will be felt dearly by many. I for one will truly miss it, the joyful lack of respect made for a good deal of laughs in an otherwise horrible news day.

Sploid, you shall be missed.

Wow, what an exciting entry I’m writing for you guys today. That’s right; I’ve switched my text editor. I know that some people out there are what I like to call “text sluts,” but I’ve been fairly true to my BBEdit. It has been my standard for years, even with its blemishes.

The difficulty in getting line numbers has constantly made debugging painful, and don’t even get me started on the lack of tabs. I could write an entire entry on how every application needs tabs, but I digress.

Regardless for those complaints, every time I’ve tried a new application, I find myself missing BBEdit. Maybe it comes from my old Emacs days, a desire to cause myself pain, or just fear of change, but nothing has been able to tear me away. Until now.

Smultron has quickly eased any fears I have had from moving away from BBEdit. I couldn’t have found a text editor that just “feels” right any more. If you are a Mac web developer, download it and give it a shot. It’s open source, but only works on Mac OS 10.4.5 or later. If you can run it, you will love it.