A little insight into the grandest of the fundamental sciences: physics.

The physicist’s condition is one of constant optimism. To solve any problem, we have to imagine the best possible scenario, and then simplify it.

This morning, for instance, I’ve been revising how to derive the 3-dimensional acoustic wave equation. I’ve completed the proof and derived an equation for the intensity of the sound, with these caveats:

1. The sound wave in question must be a plane wave.
2. The wave cannot lose any energy as it travels.
3. The wave cannot become more dispersed.
4. The equation only considers one direction of travel (along the x-axis!).
5. The equation does not work for loud sounds (i.e. large wave fluctuations like those given out by a super-sonic jet, or perhaps by your mom, when she yells at you to come in for dinner).

Obviously, more complicated equations exist, and computers solve many equations that would be difficult to solve on paper. But at this level, physics is a blue sky science, all about ideal conditions.

Unfortunately, the real world’s more complicated, and I have to get back to work! Next revision stop: room acoustics.

My father would have been 62 years old today. They just got fresh snow in Anchorage, so I bet he’d be snapping into his bindings and heading out for a wilderness trek on his cross-country skis. I wish I could join you.

Three cheers for all things dad!

I HAD THREE FIRSTS TODAY:

1. I broke my 5k running record. Current time: 26:20.

1. I ran 6k in one go. Current time: 32:45.

1. I scripted the first draft of my 20 second pitch for Saturday’s competition. This will be the first formal business pitch for my cycling product. I’m eager for the experience, and the feedback.

I’m a little nervous, but the good news is that with two days to go and only 20 seconds of pitch to practice, I can rehearse at least another 8640 times.

Update (7 Feb 2010, 12:41): The pitch took place at approximately 16:06:40 in Glasgow yesterday. Fourty-odd students competed. I didn’t win the money, but I did take second place. It was a great experience, with some room for improvement. I’m still aiming for the national finals.

Earlier this week, my friend Russell was run over by a woman driving an SUV. He was cycling down a road in Washington, D.C. She was a doctor, trying to leave Georgetown Hospital. She didn’t see him. Russell was knocked from his bicycle, and she drove over his left leg.

Before we go any further, I should tell you: Russell’s fine. One-hundred percent intact. That’s the first problem with running him over. I cracked my humerous and underwent surgery after slowly running my bike into a curb. Russell was struck by a car, and then run over, and it didn’t leave a mark. That’s not exactly fair.

The second problem is that Russell now thinks he’s invincible, and that’s a bad attitude for a cyclist to have. Fortunately, there’s some physics we can draw on to explain what really happened that night.

The car ran over Russell’s femur, the strongest bone in the body. The internet suggests a femur can withstand up to 600 lbs of vertical pressure. Russell is a young man who doesn’t suffer any particular bone abnormalities, and we know he rides his bike. So we can assume that his femur is of at least average strength.

A small SUV might weigh an imperial ton, or 2000 lbs. Divide that into the weight supported by each tire (500 lbs), and you find that a small SUV would have trouble breaking Russell’s leg.

However, a large SUV could weigh as much as four tons, or 8000 lbs. It could do some serious damage. That’s where the suspension comes in. If only one tire rolls over the leg, the wheel will simply compress the suspension on that side, and distribute the extra weight of the car to the other tires.

Just how far can the suspension be compressed? A PT Cruiser has an 8.5″ suspension traveling distance. That’s certainly higher than the height of Russell’s squashed leg. The suspension on a Land Rover can travel a respectable 7″. In short, without even considering the supporting role of the ground under Russell’s leg, we’ve determined his limb was already likely to survive the accident intact.

Unfortunately, just like for every other great feat ever performed, a simple physics explanation lies just behind the magic. I’m just glad the physics worked, and I didn’t have to write a eulogy instead.

Two electrifying programmes came across the airwaves this week. (Or in my case, wobbled through the air via the wireless router. Another blow for alien enthusiast Frank Drake.)

The first was President Obama’s appearance at the Republican Party’s retreat in Baltimore. In an hour-long broadcast, he responded to questions from GOP representatives. It was intense, entertaining and enlightening.

Republicans said that the Democrats were aggressively controlling all business in the legislature, and limiting their access to the president. Obama told Republicans that they had painted themselves into a political corner by consistently condemning Democratic proposals. For the politically inclined, it was phenomenal entertainment.

The week was also the final match of the Australian Open: Federer vs. Murray. Federer is a tennis god: sleek, cool, colour-coordinated and majestic on court. When he wants to challenge a call, he simply waves his racket nonchalantly toward the ref.

Murray is a British hero–the country’s only chance at a serious tennis victory in nearly a century. Unfortunately, he’s also young, gawky, and has the reputation of being downright dour. Though I have an ingrained desire to support underdogs, even I couldn’t root too hard for Murray.

Television is typically full of so much rubbish that I gave my set away. This week, I wished for it back! I know that not every programme can be about a world championship sports game or cover a historically significant debate, but is there any reason for shows like “Britains Missing Top Model”? Or “Bridezilla”? I’ll never race home to watch that crap, and I’ll never set my Tivo to record it. Why is it so hard to find compelling content on TV when the web does so well?