# Physics of the Water Rocket

I said I would come back to this, and I am. I am a man of my word. Yesterday, I posted a link to a video of this really cool water rocket thingy. How does this work? What is the physics going on here? I think this can be best explained with the momentum principle.

# Real Water Rocket Guy – Analysis to come

I saw this on Hack a Day, but I am sure it has been posted in other places also (seems like something that would be on Swans on Tea). Check it out. Amazing New Water-Powered Jet Pack – Watch more free videos Some pretty cool stuff. I am pondering the questions to be answered right…

# Gas + Fire + Basketball + Newton = bad idea

First, don’t play with fire. Fire is dangerous. You can get hurt. Here is a video of two guys trying to (presumably) make the Miami Heat flaming basketball. Note: the above is just a picture link to the actual movie. Embedding the movie was doing some weird stuff. In the movie, two guys pour gasoline…

# Time Warp Samurai guy – waves of kinetic energy?

I 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.…

# Basics: Collisions (Interactions between two objects)

Pre 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…

# Physics and directly downwind faster than the wind (DWFTTW) vehicles

A commenter (Joe) suggested I look at vehicles powered by the wind that can move faster than the wind. This also came up on Swans on Tea. One of Joe’s points was that I should do this BEFORE MythBuster’s gets to it. And so I shall. I know this is one of those topics that…

# Spring Motion and Numerical Calculations

Maybe you know I like numerical calculations, well I do. I think they are swell. [VPython](http://vpython.org) is my tool of choice. In the post [Basics: Numerical Calculations](http://scienceblogs.com/dotphysics/2008/10/basics-numerical-calculations.php) I used vpython and excel to do something simple. I will do that again today (in that this problem could also be solved analytically). However, there is one…

# Basics: Forces and the momentum principle

**Pre reqs:** [Free Body Diagrams](http://scienceblogs.com/dotphysics/2008/09/basics-free-body-diagrams.php), [Force](http://scienceblogs.com/dotphysics/2008/09/basics-what-is-a-force.php) The time has come to look at things that are NOT in equilibrium. The most basic question to ask yourself is: *”What do forces do to an object”*? Aristotle would say that forces make things move. Constant forces make things move constantly. Actually, Aristotle said there were two types…

# Bullets have a lot of kinetic energy (apparently)

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…

# Physics of Linerider III: Air Resistance

There is no air resistance in line rider. Sorry to spoil the suspense. To test for the presence of an air resistance force, a track was created that let the rider fall. ![linerider air 1](http://scienceblogs.com/dotphysics/wp-content/uploads/2008/09/linerider-air-1.jpg) (note the markers on the side. These are used to keep track of how the origin is moving). Below is…