kinetic energy

Note: This is an old post from the time before my blog was in wordpress. I noticed there was some incoming link for this, and I never moved it over. Here it is in it's unaltered (except for this part) format. I don't know why I even suggest a new energy source. Fusion power is only a few years away in the future (just like it as always been). This will replace any other sources of energy that we could come up with. But, I can't help myself, I need to share my idea and save the world. It's what I do. (call me a superhero is you want). We can get all of our energy from the rotation of the…
Maybe this isn't the best video to analyze, but it sure is funny. I am not sure why it is so funny - maybe you should just watch it first. Sledgehammer Funby Stressmaker I don't really know why these guys are putting explosive on sledge hammers. Sure it looks fun, but I think I would pass. Anyway, here is the part I was curious about. Did the exploding hammer lift him off the ground, or did he jump as a reaction to the explosion. It kind of looks like he was lifted, but I am not sure that is possible. Video analysis to the rescue. (using Tracker Video) So, I assumed the sledge hammer…
I made a gamble and my gamble failed. It really wasn't my fault. In the preview, they showed this huge barrel thing dropping on a see saw. It looked something like this: (I could search for 30 minutes for a picture of this online, or just draw it) At first glance, this looked JUST like that video of the pile driver shooting the skydiver up in the air. You can see how I would make that mistake. To make up for my mistake, I will give a very simple analysis of the see saw myth. The basic idea is that something comes down, hits the see saw and sends the other thing flying up. If I assume…
Another electric motorcycle post. (Here is the post on the wind-recharged drag racing motorcycle) This new one is a solar powered motorcycle. The site claims that the bike can go 50 miles on a full charge (from Gas2.org). This is easily possible, but how long would it take to charge with normal solar panels? Here is an image of the bike. Questions to be answered: How much energy would the bike need to go 50 miles? How much power (average) could you expect to get from the solar panels? And...how long would it take to charge this sucker. I am sure you can store enough energy in a…
Last night was Wednesday, so of course I watched Mythbusters. You never know when a good blogging opportunity will come up. I could talk about the kinetic energy of arrows, but instead let me talk about their episode for next week. I only caught a glimpse of it in the preview. It looks like they are doing something about jumping on a see-saw and launching the other person. It could be this video they are looking at: EMBED-Extreme Catapulting - Watch more free videos From my analysis of this video, I found that the likely outcome was a broken board (if it were not fake). Also, if the…
I just realized that something has been bothering me. It is this KillaCycle - the electric zoom-fast motorcycle that I posted about previously. It clearly is super fast. However there are two claims that seem iffy. It can be recharged in 4 minutes. It is recharged by wind power. It may be possible that these individually could be true - but could it be recharged in 4 minutes by the wind? I am not sure. Let me do some estimations to see if this is possible. What am I starting with: From the review on gas2.org, uses cordless drill batteries. Uses 1200 batteries Produces 500 bhp - not…
I 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…
I saw this video posted on Physics and Physicists: It reminded me that I had at one point tried to analyze this. I had actually posted something about this on the first generation of my blog (which no longer exists). I have found the analysis, and here it is from the archives. Thanks ZZ for reminding me. Could this be true, or is it fake? I started to do an analysis of the trajectory, but I found the following frames: Look at the guy's back. His back starts moving before the water bottle rockets. It must be some type of cable pulling him. If the rockets were propelling him, the rockets…
I finally saw the movie Iron Man. It was good. I feel that I am qualified to evaluate the movie. When I was in high school, I was totally into comic books. Mostly Spider-man, but I still have a significant collection of Iron Man comics. Ok, now you know I am not an Iron Man attacker. I will now attack the movie. Sorry, it's what I do (remember, I already said I liked it). There are several things I could comment on, in fact I recall some other blog talking about the physics of Iron Man. My attack will center on the scene where Tony Stark (Iron Man) escapes from captivity with his home…
Here is a video of a guy jumping 35 feet into a pool of water only 1 foot deep. UPDATE: Apparently, that video went away. Here is another version. How does this work? I don't think I even need to do a video analysis of this motion, all the important info is given. I will assume that air resistance did not play a signficant role (and that is a good assumption - or good enough - see this for example: motion of a falling tennis ball). So, here is the situation. Part 1: guy falls 35 feet 5 inches (10.8 meters). ![Screenshot 16sd](http://scienceblogs.com/dotphysics/wp-content/uploads/2008/11/…
On MythBusters this week, Adam and Jamie tested the bullet-proofness of various objects. The one that sticks in my mind is the ipod. The said there was a report of a solider being shot by an AK-47, but he was saved because the bullet hit his ipod. To test this, Adam shot an AK-47 at an ipod and it went through. Their conclusion was that he was also wearing body armor. I am not sure I like that conclusion. Why would someone report that the ipod saved him if he was also wearing body armor? Maybe they would, but not sure. I was thinking, maybe the bullet went through the ipod because they…
I don't need to explain that I think the Mythbusters are awesome (do I?). I just finished watching their latest episode. In it, they tested the scene from Indiana Jones and the Last Crusade where Indy puts a flag pole in another motorcycle wheel. The result in the movie is that the motorcycle goes flipping in the air. I have no problems with their test - it seems like they did a decent job. However, in the end, Adam says something to the effect: *"Look how high that bike went. It took a lot of energy. There is no way that energy could come from this stick I shove into the wheel."* I am…
**Pre Reqs:** [What is a Force](http://scienceblogs.com/dotphysics/2008/09/basics-what-is-a-force.php) [Previously, I talked about the momentum principle](http://scienceblogs.com/dotphysics/2008/10/basics-forces-and-the-moment…). Very useful and very fundamental idea. The other big (and useful) idea in introductory physics is the work-energy theorem. Really, with work-energy and momentum principle, you will be like a Jedi with a lightsaber and The Force - extremely powerful. Well, what is work? What is energy? How are they related? In [another post, I talked about energy.](http://…
I think it is time for me to talk about energy. My ultimate goal is to give some insight into the many stories about perpetual motion. To do this, I will first talk about the fundamentals of energy. **What is Energy** I started thinking about this, and at first I realized that I did not have a good, short explanation of energy. The most commonly used definition in science text books is: *Energy: the ability to do work (or something dreadfully vague like this).* But what is work? It may be no surprise to find that many college level physics texts avoid defining energy. After some serious…
I was recently re-watching a MythBusters episode and I found something I had wanted to explore previously (but accidentally deleted the episode). Here is a short clip from the "shooting fish in a barrel" episode: Did you see what I found interesting? That big barrel of water left the floor from being hit by a bullet. The question here is: Does a bullet have enough energy to increase the gravitational potential energy of the barrel to that height? First, let me gather some data. From the episode, the Mythbusters were firing a 9mm pistol round into the barrel. I don't know much about…