No new episode of Mythbusters this week, unfortunately, but in its absence I get to write about Car vs. Rain, the episode originally aired three weeks ago. It focuses on a fantastic physics-based myth: when driving a convertible in the rain, does less rain get in the car if you step on the gas, as opposed to pulling over and putting the top up?
“Does anyone have the phone number of the Internet so we can order a sendmail?”
Apparently air bags may be harmful to your thumbs. Oh noes.
I can think of some other things that are harmful to your thumbs, too. Like, say, DEATH. Am I the only one who’s never met a dead guy with full use of his thumbs?
This from the PGF manual:
Do not feel afraid of a 5-line caption. (Your editor may hate you for this. Consider hating them back.)
Someday I’m going to write an entire paper in a caption.
I probably should have started planning before 12:30 AM last night ;-) Not because there’s much to do, but because I’ve been too tired to convince myself that there’s not much to do. I guess I’ll be making it up as I go again. How hard can it be to make up a good 5-minute lecture?
This week the Mythbusters tackled the question of whether you can make a bullet follow a curved flight path, as in the movie Wanted. The characters in the movie are able to do this using some fancy flick of the wrist as they fire the gun, but is it really possible? Apparently a lot of people were wondering.
The short, simple answer is no. It’s an obvious application of Newton’s first law of motion: objects moving in a straight line will continue moving in a straight line at constant speed, unless subject to an external force. But there are only a couple of external forces that can act on a bullet: air resistance and gravity. Gravity certainly isn’t going to make the bullet curve sideways as we see in the movie, and all air resistance will do is slow it down, not change its direction.
Then again, Kari, Grant, and Tory hit on an important point: bullets are highly symmetric and are typically ejected from the gun barrel with high spin. All this is optimized for motion in a straight line toward whatever you’re aiming the gun at. What happens if you use asymmetric, oddly shaped …
Here’s something interesting that came up on Slashdot today: scientists at the Israel Institute of Technology report having created an “acoustic black hole”, a region from which no sound waves can escape, just as a normal black hole is a region from which no light waves can escape.
How did they do it? Well, whenever sound travels through a medium, it does so at a characteristic speed — about \(\unit{343}{\frac{\meter}{\second}}\) in air, for example. That speed is relative to the medium, though, so if you can get the medium to move through your lab at a faster speed, the sound waves won’t be able to propagate fast enough to move against it (relative to the lab). If you had a wind tunnel blowing air to the right at \(\unit{400}{\frac{\meter}{\second}}\), the air would carry along all sound waves traveling through it, even those emitted in the leftward direction. Any sound waves produced at the right end of the tunnel would be stuck there — in effect, it’s a one-dimensional acoustic black hole, with an event horizon at the point (surface, really) where the air accelerates past the speed of sound as it …
Congratulations Microsoft, you managed to find 3 people who don’t want to buy a Mac. Forgive me for not being totally sold.
Now what happens when you stick Linux in the mix? ;-) PC - $300 = …
I feel bad about not posting anything here for a while. This will remedy that and tide me over for another couple of weeks or so.
I did a software upgrade on my server a while ago that screwed up all sorts of things, so now I'm rewriting my website codez yet again. I promise it will be finished... sometime. In the future. I think.
I just wonder what happens when all the kids who have joined "no parents on Facebook" groups become parents themselves? Are they going to voluntarily drop off the face of Facebook?
Probably not... can't wait to catch them on it, though. ROFL