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Category archives for physics

More on turning and braking

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…

Some more info on basketballs

You know I have trouble letting stuff go, right? I am still thinking about these crazy long basketball shots. Here are some more thoughts. Really, there are two things I am interested in. First, commenter Scott Post suggests that the drag coefficient might be around 0.25 instead of 0.5. I don’t know. For the discussion…

Potentiometer for angle measurements

There is something I am working on that will need some type of angle sensor. I am going to use a potentiometer. First, who came up with that name? Isn’t this name the same as a voltmeter? Something is wrong with that name. How about we just call it a variable resistor or something like…

Kindle vs. iPad in the Sun

There is this commercial that has been coming on lately showing some people reading the Kindle at the beach. Why is this a selling point? It has to do with the way the Kindle works compared to something like the iPad. I would take a picture, but I have neither of these devices. Instead, I…

This summer I taught the part II of algebra-based physics. It is odd, but I rarely teach this course. I usually end up teaching the calculus-based version (with Matter and Interactions). There is something strange. If you look at the algebra-based physics I and calculus-based physics I, they are just about the same course. Both…

Basketball shot – real or fake?

I have seen several videos similar to this. Real? Fake? How many tries did this take? Let the analysis begin. Before I do any analysis, let me state that I think this is not fake. I do not know that for sure, just my first guess. How would I tell if it is real or…

Turn or go straight? Quick!

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…

What makes a good post?

First off, I think this is a really good post (not this self-referring post, but the post I am about to link to) Steak Dinner by Alemi at The Virtuosi In short, this post is about cooking steak and the measurements of the temperature of the meat. Why do I think this is a good…

How fast is the Beacon of Gondor?

The Lord of the Rings trilogy came on TV again recently. My wife and I can’t help but to watch this even though we have it on DVD. Anyway, I was thinking about the part where Gondor sends a signal to Rohan asking them for military aid. Since this was before the invention of email,…

Paranoia, it’ll destroy ya

Check this out – NY Times: No Motors, but Mistrust at Tour de France. So, the short story is that some people claim that Cancellara is cheating by putting a hidden electric motor in his bike. Now they are going to do random hidden-motor checks. I have analyzed this motor-in-a-bike already: Energy in a hidden…