centripetal
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Category archives for centripetal
Pouring tea in a plane – upside down
Posted by Rhett Allain on August 17, 2010 Let me start with the video. Here is a guy flying a plane in a barrel roll and pouring some tea at the same time. Talk about multitasking. How can he pour upside down? Well, there are two ways to look at this. First, I can look at this in the frame of the plane.…
More on turning and braking
Posted by Rhett Allain on August 16, 2010 I can’t let it go. There is more here to explore. First, I can’t believe that I looked at braking and then turning but not turning then braking. And what about braking while turning? I will model braking and then turning – but it won’t stop here. Consider a few motions. I could turn and…
Turn or go straight? Quick!
Posted by Rhett Allain on August 5, 2010 This is a classic problem. You are in a car heading straight towards a wall. Should you try to stop or should you try to turn to avoid the wall? Bonus question: what if the wall is not really wide so you don’t have to turn 90 degrees? Assumption: Let me assume that I can…
Mercedes Roll
Posted by Rhett Allain on July 13, 2010 Here is a commercial for some Mercedes car. The first part is quite boring, but check out the stunt at around 2:00 minutes into the video. I haven’t bothered to check if this is officially fake or not. Instead, I will do what I do – see if this is even feasible. The common question…
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…
Where is the accelerometer in an ipod touch?
Posted by Rhett Allain on April 27, 2010 There are several free iPhone-iPod Touch apps that let you look at the acceleration of the device using the built in accelerometer. I was planning on reviewing some of these free apps, but I didn’t. When I started playing around with them, it was clear that I needed some way to make a constant acceleration.…
RP 11: When the centrifugal force is the centripetal force
Posted by Rhett Allain on January 1, 2010 It’s odd that I have talked about these forces so much. First, I talked about how centrifugal forces were not real and the difference between centrifugal and centripetal forces. Then I talked about how sometimes, fake forces are good. Finally, I talked about the origin of the words centrifugal and centripetal. (note: “talked about” means…
More Punkin Chunkin Centrifugal Machine
Posted by Rhett Allain on November 27, 2009 This year’s episode of Punkin Chunkin is coming up (I think tomorrow). Discovery just showed a teaser commercial with the specifications for one team’s machine. If you are not familiar with Punkin Chunkin (World Championship Punkin Chunkin), the basic idea is to project some pumpkins. (note, if you waiting for the Discovery Channel show for…
Punkin Chunkin – why work to be wrong?
Posted by Rhett Allain on October 31, 2009 Here is the deal. Why would you put a lot of effort into explaining something wrong? I just don’t get it. Wouldn’t it be easier and better to just not say anything? The particular show I am ranting about is the 2008 Punkin Chunkin on Discovery (I think). Fairly ok show, but they should have…
Demo: How to not spill your drinks
Posted by Rhett Allain on October 27, 2009 I know I saw this demo somewhere. Maybe it was at an AAPT conference a few years ago. I have always wanted to build this, but never got around to it. Until now. Here is the demo (it is easy, you should make one too) So, how does this work? I think the simplest explanation…