# Terminal velocity

I recently read Ancillary Justice, the Hugo and Nebula award winning novel by Ann Leckie and enjoyed immensely, but it had one paragraph that brought me up short. The reason involves fluid mechanics, so it seemed like a good topic for a blog post. But first the book. Ancillary Justice has a good story, but…

# Energy dissipation in damped vibrations

In the previous post in this series (which was four months ago—time flies), we looked at the free vibrations of damped single-degree-of-freedom (SDOF) systems, systems that can be modeled as a spring-mass-dashpot like this: The position of the mass, [u], can be expressed as a function of time, [t], through the formula [u = A…

# A brief construction bestiary

This post was inspired first by Marco Arment and his son, Adam: Fake Cheerios are better from a backhoe. @ Mont Olympos Restaurant instagram.com/p/rhVYe4w5Ii/— Marco Arment (@marcoarment) Aug 10 2014 9:18 AM Click the Instagram link to see Adam using a clever spoon substitute. My predictable reaction: @marcoarment I love the photos of your son…

# Damped free vibrations

The second simplest vibrating system is composed of a spring, a mass, and a damper. We’ve seen the spring and the mass before, so let’s talk about the damper. The image typically used to represent a damper is meant to look like the cross-section of a hydraulic cylinder1 with a leaky piston, a device called…

# Energy and gravity

At the end of the previous post on vibration, I said the next one would be on damped systems, but I’ve thought it would be best to discuss a couple of side topics before we move on: energy and gravity. The mechanical energy of our spring-mass system is composed of two parts: the kinetic energy…

# Siracusa-Fu

Generally speaking, I think it’s cheating to use what John Siracusa says as a topic for a blog post. I could get 2–3 posts out of almost any episode of Hypercritical or the Accidental Tech Podcast (except for the ones about games, which hold no interest for me), just filling in odd details and expanding…

# Bridge failure

This afternoon, as my wife pulled her reading glasses out of their case in her purse, one half stayed in her hand while the other half clattered on the floor. They were broken through the center of the bridge. When we got home, I took a look at them in good light to see why…

# Screwed up

I’m deeply disappointed in each and every one of you. Last night, in the post about jacking up a bed to remove the headboard, I said The jack’s leverage, meant to lift a car, was so great I could lift the bed by turning the screw with my fingers. and none of you took to…

# Wind engineering

When I first heard reports about the wind speeds in Typhoon Haiyan, I assumed it was case of journalists getting their facts wrong. But as those early reports were repeated, and as I saw photos of the devastation, I realized that the initial reports weren’t wrong—Haiyan was an unbelievably powerful storm. Twenty years ago, I…

# Hyperloop

The Hyperloop is a futuristic, high-speed transportation system dreamed up by Elon Musk, of PayPal, SpaceX, and Tesla Motors fame. The idea is that you and a couple dozen other travelers get into a capsule that’s loaded into a pneumatic tube and whooshed away at several hundred miles per hour. It sounds like Victorian-era science…