## Friday, September 14, 2012

### Physics Can Be Hilarious

Physics can be really funny. Exactly how funny? Well, I'm alone right now and was laughing out loud not moments ago. As demonstrated by the following two videos (and a brief conceptual analysis thereafter), we can see that physics plays a fundamental role in all areas of our life, even the happy ones (though these people are probably not too happy).

What makes us laugh here? While one may not readily intuit it, its the person's very rapid deceleration, which causes an almost instant decrease of velocity to zero. Take our simplest kinematic equation: vf = vo + at. We know that vf equals zero at the moment of impact with the glass. Let’s assume vo, or initial velocity, equals he average human walking pace, which the internet tells me is 5.0km/hr, or 1.3m/s. The final variable we are going to assume we know is t; granted, I don’t actually know how long it takes for the person to stop moving as a result of running foolishly into a wall, but I think a very rough estimate would be somewhere between a tenth and a hundredth of a second (t = 0.05s). Putting these variables together, we get 0m/s = 1.3m/s + a(0.05s) --> -1.3m/s = a(0.05s) --> a = -26m/s2. That’s really fast deceleration for just walking. And thankfully really funny too.