collision
esiegel | December 11, 2013"Where you used to be, there is a hole in the world, which I find myself constantly walking around in the daytime, and falling in at night. I miss you like hell." -Edna St. Vincent Millay
It was just a little while ago that we were all speculating wildly -- and optimistically -- about Comet ISON, as it plunged towards the Sun from its origins in the very, very distant Solar System. As its perihelion date (the moment of closest approach to the Sun) drew near, you may have noticed something interesting about photos of the comet: it's tail appeared to get longer and longer!
Image credit &…
esiegel | December 6, 2012"Forget it. I didn't have that thing inside me where I wanted to smash against somebody and watch them break. I was too sensitive for that and disliked being that sensitive." -Josh Brolin
How do you figure out what something is made of? You take it apart -- cracking it open if necessary -- and look inside. This is something we've been doing since... well, since before our ancestors were even human.
Images credit: Elisabetta Visalberghi.
For most things here on Earth, that's easy enough. If you wanted to go down to the smallest scales possible, however, it becomes harder and harder to "crack…
esiegel | August 17, 2012"We don’t understand how a single star forms, yet we want to understand how 10 billion stars form." -Carlos Frenk
The Universe has been around for a long time: nearly 14 billion years, to the best of our knowledge. When it was very young, there were absolutely zero stars in it, while today, there are hundreds of billions of galaxies, each of which contains anywhere from a few billion to many trillions of stars.
Image credit: NASA, ESA, and the Hubble Heritage (STScI / AURA) - ESA / Hubble Collaboration
The galaxy shown above, NGC 2841, is very similar to our own Milky Way. Approximately the…
rallain | August 20, 2010Reader Jorge has also looked at these amazing basketball shots. (here is my last basketball analysis) Jorge claims that at least one shot seems fake. He is referring to the following video (at around the 2:20 mark).
ARRGH Ok, new plan. For some dumb reason, youtube won't let me embed this video. Well, here is a link - Amazing Basketball Shots: The Legendary Shots 4 (at least I can link to the right time). It is even dumber that you can't embed it, but youtube gives you the download option. Oh well.
Let me tell you the part that Jorge has an issue with. This guy on a ladder throws a…
rallain | June 10, 2010In the last episode of MythBusters, they wanted to see if a tornado could make some glass cut off a person's head. The first attempt was just to take some glass and through it at a simulated human neck. Clearly, this wasn't quite the same as a tornado.
So, here was their plan. If they want to simulate glass moving at 300 mph, they could get a bigger piece of glass and put it on a truck moving at 80 mph. The result would give a piece of glass with the same kinetic energy as a smaller piece moving at 300 mph. Their calculations look to be correct. However, the question is: would this make…
rallain | April 19, 2010You probably already know how I feel about the "media" and their physics explanations (see attacks). Let me summarize the problem. There are a whole bunch of cool shows on tv that deal with sciency stuff - that is good. These shows then try to teach some science along with their demos and explosions and stuff. This is also good. However, they usually butcher the explanation part. Some of them (ESPN's Sport Science) must just literally make stuff up that sounds cool.
I understand that in common usage, things like "force" can be used lots of different ways. I am ok with that. Also,…
rallain | December 10, 2009Have I not made it clear how much I like the MythBusters? Also, I am totally aware that they are not (nor do they claim to be) scientists. Really, this is what makes their show appealing (maybe?). So here is the problem now. And, it is not just the MythBusters - I see other shows making the same mistake.
If two things are colliding, how do you characterize the collision? No one really gets this right. For this particular episode, the MythBusters were looking at the collision between a bullet and gun. They wanted to see how hard it would be to shoot a gun out of someone's hand. The…
rallain | September 28, 2009I think we are entering a new era. An era where it is quite simple to find and get great videos. Oh, just saw a great tackle on the TV? In the old days, you would have to get that video off the TV yourself. Not anymore. Welcome to the interwebs. Also, the quality is awesome compared to 10 years ago. Here is the video. Yes, I know this is from several weeks ago - I am slow. Also, thanks to the person that put this on youtube - I edited your clip to remove the music and just look at the one collision. You did a good job though.
In terms of video analysis, this isn't too bad of a video…
rallain | April 10, 2009I am so pumped up that MythBusters is back on. Not only do I like the show, but it offers so many blogging opportunities. Their latest show featured car crashing myths. One of the myths from the episode was a redo of the myth where two trucks crash head on simultaneously crushing a smaller car in the middle.
The first test was very similar to the previous time they tested this, but faster. They towed two 18 wheelers to crash together around 50 mph and smash a stationary car. The results were impressive. However, they did not have the result of the car completely contained in the…
rallain | February 26, 2009First, I think we should all be using smaller lighter cars. They get better gas mileage, they are better for the environment and maybe even reduce traffic? (ok, not sure about that last one - but it is possible). In Buzz Out Loud 918, they were discussing Toyota working on new car bodies built from sea-weed based plastics (from a wired article). One point that was brought is the comparison between old plastic bodies (the pontiac fiero comes to my mind) and these new plastics that should be much stronger. Well, here is the problem. Light strong bodied cars can be dangerous. Really? Yes…
rallain | February 3, 2009People say I am picky. Ok, sometimes I am. But somebody has to stand up for what is right and just. Maybe I am that person.
Please stop using the word force if you don't know what it is.
There. I said it. You can attack me now.
It wasn't just one thing that got me fired up. It was two things. First, I read this article on physics and football (Physics of 'The Hit' from the NY Times). If it was just this article, I would have let it go and moved on. But no. One of my kids just happened to be watching MythBusters (We all love MythBusters) and there was a discussion that used the term…
rallain | December 19, 2008I am sure I have mentioned the Discovery show Time Warp before. The basic idea of the show is to find how many cool things they can look at with an ultra slow motion video camera (btw - this is on my christmas list).
So, I have seen this Samurai guy on the show twice. Yes, he has a big sword. Yes, he could utterly destroy me if he wished. However, I can not handle him talking about physics. Mr. Samurai guy, please stop using the words "kinetic energy" until you know what they mean (I said please). Here is my first problem. Samurai guy is showing how to chop people down. He plans to…
rallain | December 12, 2008Pre Reqs: momentum principle, forces,energy, vectors
Really, there is not much new here. This is an introduction to objects that interact. To describe this, I will need to pull several different ideas together (that you have probably already looked at). Let me start with a simple case. Suppose I have two objects, maybe they are two asteroids in space. I will call them asteroid A and B:
In this situation, the two objects have different momentums but one interaction between them. Notice that the gravitational force on asteroid A is the same magnitude but opposite direction as the force…
esiegel | May 8, 2008Let's say we're having a nice day here on Earth; the Sun is shining, the clouds are sparse, and everything is just looking like a peach:
And then Lucas goes and tells me,
Oh my God, Ethan! It's Armageddon! An asteroid is coming straight for us! You've got to stop it!
Really? Me? Well, how would I do it? Let's say we've got some reasonably good asteroid tracking going on, and we've got about 2 months before the asteroid is actually going to hit us. We'd like to do something with the situation on the left, to avoid the situation on the right:
Well, what we really have to do is change the…