free body diagram

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What is Arnold made of?

Of course I am talking about Arnold Schwarzenegger. After looking at how many bullets he carries in Commando, I remembered this scene (also from Commando) (warning: maybe some not great language and some killing. You have been warned) If you don’t want to watch that clip, here is a shot (sorry for the quality). Clearly…

Stratos Jump for Mere Mortals

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…

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

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,…

Pressure demo: suction

How does a suction cup work? It is all about the atmosphere. Here is a demo. Take some type of “suction cup” device. In this case, I used a toy dart. Stick it to something smooth and lift it up. Like this: What lifts up the metal block? The atmosphere. Diagram time: But this isn’t…

Yo-Yo: Rolling, sliding, pulling

This is actually been sitting around for a while waiting for me to post it. Here is another short Christmas-toy demo. I am going to pull this yo-yo at different angles and on two different surfaces. Check it out. What is going on here? Let me look at the first case where I pull the…

In a MythBusters episode some time ago, Adam and Jamie jumped off a building. There was some cool stuff in this, but I want to focus on the acceleration data they collected. Before jumping into a pit of foam, they first wanted to test the set up by dropping a dummy into it and measuring…

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…

RP 6: Throwing a fooball, Part II

In part I of this post, I talked about the basics of projectile motion with no air resistance. Also in that post, I showed that (without air resistance) the angle to throw a ball for maximum range is 45 degrees. When throwing a football, there is some air resistance this means that 45 degree is…

On a previous episode of The MythBusters, Adam and Jamie made a lead balloon float. I was impressed. Anyway, I decided to give a more detailed explanation on how this happens. Using the thickness of foil they had, what is the smallest balloon that would float? If the one they created were filled all the…