Archive for September, 2008
Pre Reqs: Intro to Forces, Vectors
Hopefully now you have an idea of what a force is and what it isn’t. What do you do with them? The useful thing to do with forces is to determine the total force acting on an object. At the beginning of the introductory physics course, you [...]
When mowing the lawn, I like to listen to podcasts. One of my favorites is Buzz Out Loud. This weekend, I was listening to episode 817 and one of the topics of discussion was MySpace and their DRM free music stuff. Wired had a description of what they were going to do. [...]
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 [...]
Pre-reqs: None.
I intend to talk about forces and force diagrams, but there is a more fundamental question to address first. What is a force? Most texts define it as a push or a pull. That really isn’t a bad definition. Maybe a better (or maybe worse) definition would be “forces are [...]
In a previous post, I talked about how to plot kinematics data with a spread sheet and how to fit a quadratic function to the data. In the back of my head I remember “Don’t trust Excel”. I seem to recall someone claiming that Excel did not do a proper fit. To [...]
pre reqs: Vectors and Vector Addition
This was sent in as a request. I try to please, so here it is. The topic is something that comes up in introductory physics – although I am not sure why. There are many more important things to worry about. Let me start with an [...]
In my classes, I like to bring up the question:
Why do astronauts float around in space?
The most common response to this question is that they float around because there is no gravity in space. Some people take this a small step further and say that there is no gravity in space because there is no [...]
pre-reqs: kinematics I don’t think you need part I of this if you don’t want
So, you still want to make a graph with that kinematics data? You think that graphs on paper are too barbaric? Well, if you are ready, you can use a spreadsheet. But be careful. If you don’t know [...]
Today I was talking about electric potential. My favorite analogy for electric potential energy is gravitational potential energy. But electric potential is something different. Electric potential (commonly called potential) can be defined as:
$$V=\frac{U_\text{electric}}{q}$$
So, V is the electric potential in units of Joules per Coulomb or Volts.
What about gravitational potential? I am [...]
I use equations quite a bit. What I have been doing is writing the equations in LaTeX and then taking a screen capture of the output. I think this makes nice looking equations, but it sure takes a while. Here I am testing LaTeX for WordPress plugin. The following should be [...]