# How do you represent vectors?

Recently, I was talking about vectors. At that time, I had to stop and recall how I had been representing vectors. Ideally, I should stick with the same notation I used in Basics: Vectors and Vector Addition. But let me go over the different ways you could represent a vector. Graphical Maybe this is too…

# An example of two collisions

Suppose you want to move an empty paper clip box by shooting it with a toy dart gun. Why would you want to do this? Don’t worry about that – this is my example and I am sticking with it. Should you shoot a dart that sticks to the box or should you shoot one…

# Science Fair for Mere Mortals

After judging the science fair last week, I would like to revisit my tips for you the science fair participant. Warning number 1 Some of the things I say here might go against what your teacher has told you. I am not sure what you should do in this case. Your teacher gives you a…

# 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…

# Seeing through windows – light and dark

Here is a picture of something you have seen before. These are two pictures of the same location in my house. The one on the left is taken when the Sun was up outside and the other one when it was dark outside. For both pictures, I had the same lights turned on inside. So,…

# AutoTracker and a landing plane

If you know me, you know I love Tracker Video Analysis. Basically, it is a free-java program that allows you to get position-time data of a moving object from a video. In Tracker version 3.10, there is now the autotracker feature. This will automagically mark the location of an object moving in a video. How…

# MythBusters, Falling, Stopping, and Integration

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…

# RP 11: When the centrifugal force is the centripetal force

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…

# Mechanics an Example of the Pendulum

This post has been sitting in my mind for quite some time. Really, it is about mechanics – not about pendulums. What is the goal in mechanics (classical mechanics, if you like)? Generally, it is to find out how something changes over time. If you could get an equation of motion, that would do it.…

# Retroflectors

One of the roads near my house was just redone. They added some awesome retroreflectors in the middle. Here is a shot. No wait, I don’t have a picture of that. I tried to take one, but it just didn’t turn out very well. Oh, you know what it is supposed to look like. It…