Irregular Webcomic!

Irregular Webcomic! #2351

Expensive vehicles need lots of maintenance. Cheap ones, not so much.

Think about how much time you need to spend maintaining a bicycle. Not really a whole lot - you'll need to replace a tyre now and then. Maybe spend 15 minutes tightening the brake cables once a year.

How much time is needed to maintain a car? It should be serviced a couple of times a year, taking several hours, and other things will need fixing or topping up every now and then.

A plane? A plane basically requires a light service after every flight, and a more thorough one several times a year.

The space shuttle... needs a comprehensive overhaul after every single flight.

There's an elegant rule of thumb that the more expensive a vehicle is, the more time is needed to keep it in working condition. Air forces generally operate under the principle that hangar time is linearly related to the cost of a plane.

The roleplaying game GURPS actually enshrined a variant of this principle in its second edition vehicle rules: Vehicle require some sort of maintenance every 20000/(square root of cost in dollars) hours. Examples of types of maintenance relevant for different types of vehicles include: scraping off barnacles, changing oil, or dismantling the engine and running computerised stress tests. If a vehicle operates continuously (such as a ship or spaceship), then it needs a number of person-hours of maintenance every day equal to 96/(number of hours). For example, a ship costing $100 million requires 48 person-hours of maintenance a day - which could be provided by a team of six or more mechanics and engineers, working three shifts a day.

It seems like an odd relationship at first, relating vehicle maintenance to price, but it works quite elegantly.

Irregular Webcomic! #2350

There is a Wikipedia page with a List of inventors killed by their own inventions. I was hoping to find someone really famous on there. Marie Curie is the most famous name on the list, but since she didn't really invent radiation as such, I felt that was kind of cheating. I settled for the Titanic engineer, Thomas Andrews, since even if people don't know his name, he's easy to describe.

I was really hoping for something along the lines of Alexander Graham Bell having died during a tragic phone booth stuffing incident or something. The cosmic irony inventory on causes of death of famous inventors is critically low.

Irregular Webcomic! #2349

Prayer wheels are an interesting invention. The idea is that reciting prayers is good and accumulates some sort of metaphysical brownie points. This is a common enough belief amongst many religions all over the world. Tibetan Buddhism takes a very pragmatic approach to this concept, by extending the idea to prayers written on physical objects, in particular cylindrical drums mounted on axles so they can be spun around. The act of spinning one of these "prayer wheels" is then essentially equivalent to reciting the inscribed prayer.

And this idea is not merely limited to spinning the prayer wheel manually. There are giant prayer wheels, hitched up to power sources such as waterwheels or windmills. These spin continuously, racking up positive karma whitout anyone actually needing to do any work whatsoever! You can also hook a prayer wheel up to a combustion engine or the mains power grid. Canonically, this still works, but using electricity to spin your prayer wheel is not recommended because the good karma accrues to the power company, not yourself. Seriously.

Human ingenuity is limitless. Who ever would have thought that you could invent a labour-saving device to save the hassle of saying prayers and building up cosmic good karma? (Well, besides the ancient Tibetan monks who actually thought of it...)

I wonder if other religions could be persuaded to adopt this approach. Can you imagine chain-driven rosary beads, accumulating hundreds of "Hail Mary"s a minute?

Irregular Webcomic! #2348

Friction is a reactive force that opposes motion, caused by the physical contact between matter moving or being impelled to move at different speeds.

The simplest theoretical treatment of frictional force defines a coefficient of friction, which is a factor that multiplies the force perpendicular to the surface of contact, to give the force resisting the motion. In the case where an object is sitting on the ground, the perpendicular (or "normal" in usual physics jargon) force is basically the weight of the object. If the coefficient of friction is 0.5, then a force equal to half the weight of the object needs to be applied to the side of the object in order to slide it along the ground.

The symbol for coefficient of friction is the Greek letter μ, or mu.

Irregular Webcomic! #2347

Have you tried not being a monster?

Irregular Webcomic! #2346

The punchline is a slight variant of the flavour text on the Magic: the Gathering card Sizzle. It was just so appropriate that I had to use it at some point.