kinematics

Dot Physics

Category archives for kinematics

Watermelon Collisions – ouch

Through random surfing, I found this clip from The Amazing Race (which is apparently some type of reality show). Don’t really know the set up except that it appears some girl is trying to launch watermelons with a slingshot. This looks bad, but she seems to not be seriously injured. Watermelon smashed on face. Wow.…

Happy g day

Actually, it should be called Happy “Magnitude of the local Earth gravitational field” day. You know, 9.8 N/kg on September 8 (9/8). Get it? Well, the idea was for the physics students and faculty to build some stuff to do outside – projectile motion type stuff. Well, we had the idea a while ago and…

More basketball analysis

Reader Jorge has also looked at these amazing basketball shots. (here is my last basketball analysis) Jorge claims that at least one shot seems fake. He is referring to the following video (at around the 2:20 mark). ARRGH Ok, new plan. For some dumb reason, youtube won’t let me embed this video. Well, here is…

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…

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…

Maxima can be useful

The other day I found myself faced with six equations that needed to be solved algebraically. Just so you know, I am a big fan of paper for most of these cases – but this was out of control. I was making silly mistakes and causing all sorts of problems. What to do? My first…

Do Bikers Cheat?

Well, maybe that isn’t the best title. You see, there is this video going around saying that it is possible that a professional bike racer was cheating by putting a hidden motor in his bike. I am not really going to talk about the cheating aspect (my gut feeling says that it would be too…

How far will the car go?

Honestly, I was going to add this to my previous post about the jumping car but I didn’t because I wanted to finish. So, here it is and more. Actually, I will just make a projectile motion spreadsheet. That way, anytime you want to do a projectile motion problem, you can come here. Maybe this…

How fast was the car going?

Reader Colin asked a great question about this popular clip. How fast was the car moving? First, a quick assumption. I will assume that the frame rate on the video is correct (meaning not slowed down). Colin already looked up the length of the Chevy Impala on Wikipedia for me. It has a length of…

Tail-Drop Analysis

I don’t know why they call it a tail drop. Here is a video: The link I clicked that brought me to this video said the equivalent of “OMG!” That is not what I thought, really I am not sure what is so impressive (except that he didn’t fall off the skateboard). If the original…