forces
Dot Physics
Category archives for forces
Experimental Rope Logarithms
Posted by Rhett Allain on June 1, 2010 Sue from Math Mama Writes… sent me an email about wrapping a rope around a pole. In that post, Sue thinks about rope looped around a post. When you wrap a rope around a post, the friction between the rope and the post can help you hold something (like a horse) that is much stronger…
Star Trek Space Jump
Posted by Rhett Allain on May 24, 2010 While I am still fresh on the Space Jump topic, let me take it to the extreme. Star Trek extreme. SPOILER ALERT But really, is this a spoiler alert if it is from the trailer of a movie that has been out forever? Of course, I talking about the latest Star Trek movie where three…
Stratos Jump for Mere Mortals
Posted by Rhett Allain on May 24, 2010 Crazy, but I was on CNN Saturday night. They contacted me at the last minute to talk about the Red Bull Stratos Jump. Here is a screen shot to show that I am not making this up (or that I have awesome photoshop skillz). Looking back, maybe I looked like an idiot. Really though, it…
Hey, look kids! There’s Big Ben.
Posted by Rhett Allain on May 20, 2010 And there’s parliament. Ok – sorry, I had to make a “Tom (Swans on Tea)” title for this one. Tom, forgive me. Here are two great circular motion videos. First, this one is from Dale Basler. He made himself a fine little floater-type accelerometer. Better than just make it, he made a video of the…
Notes on the Physical Science Final Exam
Posted by Rhett Allain on May 17, 2010 Grades are in. So, let me just say a couple of trends that I saw on the physical science final exam. Gravity on the moon I asked the question: “why is the gravitational force on an astronaut less on the moon than on Earth?” The simplest answer is that the gravitational field on the moon…
Flying R2 in simpler terms
Posted by Rhett Allain on May 17, 2010 Galactic Binder (a Star Wars fan site) invited me to write an article for them. Obviously, I said “yes”. But what to write about? I decided to write a different version of my flying R2-D2 post. What is different? In my original post, I go into a lot of details. Essentially, that post is like…
Preemptive MythBusters: Giant Water Slide Jump
Posted by Rhett Allain on May 16, 2010 I am excited. This Wednesday, the MythBusters are doing the giant water slide jump. Maybe you are new to the internet and you haven’t seen this video. Here it is: And since it is as old as the hills, of course I have already analyzed it – actually twice. First, the video is fake –…
A small duct tape mistake
Posted by Rhett Allain on May 13, 2010 Yes, I am going to talk about the MythBusters latest duct tape episode. A couple of pre-post points: They call it “duct” tape. I call it duck tape. It doesn’t work very well with ducts. Also, it is good for water proofing stuff – you know like a duck. For the rest of this post,…
MythBusters’ energy explanation
Posted by Rhett Allain on May 6, 2010 I already mentioned the MythBusters’ crashing two cars episode where they correctly doubled the speed of a pendulum type object. Overall, this was a very visual (although expensive) demo. There was one part that left a sour taste in my mouth – the final explanation from the narrator. First, they showed this. And then they…
Another example of a dangerous jump
Posted by Rhett Allain on April 24, 2010 Check this out. So, the guy jumps from 150 feet into some cardboard boxes. Why are the boxes important? You want something that can stop you in the largest distance to make your acceleration the smallest. Here is my Dangerous Jumping Calculator. Basically, you put in how high you will jump from and how much…