Stair Power!

Let’s say I, a human male massing 132 kg and carrying a 9-kilogram box of dusty old knick-knacks and other junk, ascend a 10-meter-high flight of stairs in 15 seconds. During that time, I’m expending 922 Watts, which is over nine times a human’s resting metabolism, and about one and a quarter horsepower.

This isn’t the start of a thought experiment. This is just my silly way of letting you guys know why I’ve been silent lately: helping people move is kind of a pain. Good exercise, though, if they, say, live on the third floor.


What’s Coming Up

Because I’ve had too much coffee and I’m all hyper, I feel like writing things. So I’m writing this thing to let you all know what sort of posts to expect in the near future.

One of the next two posts will be part of my Cars series, in which I use awesome physics game BeamNG Drive to simulate what it would actually be like to drop a turboshaft engine into an ordinary car, and all the practical hurdles you face on the road to 500 mph.

The other will be a standalone post going through the math and trying to decide whether it’s possible to have a self-sustaining community on wheels. A little all-terrain rolling town, in other words. It’s gonna be full of cool stuff like pictures of gigantic dump trucks and mining equipment, along with crappy drawings of cruise ships and skyscrapers on wheels. Don’t miss it!


I Wrote a Book!

You may have noticed I’ve been promising new post and not actually writing them. Part of that is procrastination (of course), but the more important reason is that I’ve been working on publishing my book.

I called it Freeze. It’s a short novel, in which a man who owns a diner is trapped by a blizzard that quickly turns North Carolina from the swampy temperate state that it is into a sub-Antarctic wasteland. If you like apocalyptic fiction or disaster fiction, you might enjoy it.

You can buy the paperback edition here for $15 US, 10 British pounds, or 13 Euros. (I think.) There’s also a Kindle edition, which is $10 US.

No pressure, of course. This is meant to be just as much of an update post as a shameless advertisement. If any of you out there read it, please feel free to let me know what you thought of it.

Cars, physics, update

A Toyota on Mars: Addendum

In the comments of my last car post, ECooperZone asked an excellent question that I didn’t even address. I have given myself a literal slap on the wrist for that, because it’s bad thought-experiment etiquette.

The issue is horsepower. I listed the horsepower of my Toyota Yaris’s engine several times, and then just sort of tossed it out, because it didn’t factor into my equations. After reading ECooperZone’s comment, I got that nagging feeling that we nerds get when an equation comes out a little too perfect, and we have to go back and pick through the steps one-by-one to see if we forgot to multiply by pi or something like that.

Luckily, the issue of horsepower doesn’t invalidate my whole thought experiment, because, as I mentioned in my response to the comment, horsepower and torque are intimately related. I found a concise summary of the relation here. The equation is shockingly, pleasantly simple:

horsepower = torque * rotation speed (in radians per second)

Remember the scene from the Arnold Scwharzenegger Conan the Barbarian where Conan becomes a musclebound superhero because some evil bastards make him push a grinding wheel for ten years?

Let’s say Conan has to apply 50 pounds of force. That’s 222 newtons. That lever-arm looks to be about 2 meters long, for 444 newton-meters of torque at the axle. The wheel isn’t turning very fast: I’d judge about 1 rotation per minute, which is 2 * pi radians divided by 60 seconds, or 0.1 radians per second. 444 newton-meters * 0.1 per second (radians isn’t an actual unit, so we can drop it) means 44.4 Watts total power, or a pathetic 0.06 horsepower (Hey, it’s a kid pushing a grindstone. What did you expect?)

That’s the relationship between horsepower and torque as I understand it. If I’ve gotten anything wrong, I’ll slap myself on the wrist again and tell y’all about it.