# What if everyone jumped?

Might as well jump. Jump. Go ahead, jump. – Van Halen Suppose everyone in the world got together and jumped. Would the Earth move? Yes. Would it be noticeable? Time for a calculation. Note: I am almost certain that I have done this before, but I can’t find where. Starting assumptions. 7 billion people. Average…

# Basics: Electric Potential for a Point Charge

Pre Reqs: electric potential, electric field, work-energy To start, remember that for a constant electric field the change in electric potential energy would be: WARNING: that is only for a constant electric field. I know you will be tempted later to use this for a different electric field, but DON’T DO IT. But if not…

# How hot would the space jumper get?

A new video from the Red Bull Stratos Jump guys came out. Here it is: This reminds me of an unanswered question about the Stratos jump that I didn’t address on my last post on this topic. Commenter Long Drop asked about how much Felix would heat up as he falls from 120,000 feet. This…

# MythBusters and double the speed

In the last episode of MythBusters, Adam and Jamie wanted to test something that Jamie had said earlier: “Two cars crashing head on at 50 mph is the same as one car crashing into a wall at 100 mph” Jamie was wrong, but that is not what I am going to talk about. Instead, I…

# Dangerous Jumping Calculator

Maybe this could fall under my “physics of parkour”. It could also apply to the MythBusters “dumpster diving” episode. In both of these cases, the question is: how far can you jump off of something and not severely hurt yourself. They do this a lot in parkour. Here are some examples: There are a ton…

# Labs to not do – mechanical equivalent of heat

Note to self: don’t do the mechanical equivalent of heat lab again. It doesn’t really work that well and there are better labs to do. So, what is the mechanical equivalent of heat lab? It is actually a pretty cool idea. Take and object and drop it. What happens to the kinetic energy the object…

# How much would “free” energy cost you?

This was on my ‘to do’ list, but Tom at Swans on Tea beat me to it. Basically, this grocery store has these plates that when depressed produce electrical energy. Tom does a good job pointing out that this is not free energy (the original article says this also). Clearly, the energy comes from the…

# Can an exploding hammer lift a guy?

Maybe this isn’t the best video to analyze, but it sure is funny. I am not sure why it is so funny – maybe you should just watch it first. Sledgehammer Funby Stressmaker I don’t really know why these guys are putting explosive on sledge hammers. Sure it looks fun, but I think I would…

# MythBusters – I was so wrong about the see saw

I made a gamble and my gamble failed. It really wasn’t my fault. In the preview, they showed this huge barrel thing dropping on a see saw. It looked something like this: (I could search for 30 minutes for a picture of this online, or just draw it) At first glance, this looked JUST like…

# Preemptive Mythbusters post – jumping on a see-saw

Last night was Wednesday, so of course I watched Mythbusters. You never know when a good blogging opportunity will come up. I could talk about the kinetic energy of arrows, but instead let me talk about their episode for next week. I only caught a glimpse of it in the preview. It looks like they…