# Watch How This Skateboarding Trick Defies The Laws of Physics

Go behind the physics of skateboarding with Physics Girl and Rodney Mullen.

Physics and skateboarding - it’s not a combination that immediately jumps to mind. But if you have ever watched a pro skateboard (or a really good amateur) you’ll see that the tricks they are pulling off - just seem impossible.

Begging the question - what is the physics of a kickflip? Luckily YouTube channel, Physics Girl had this question too and teamed up with one of the world's best skaters, Rodney Mullen,  to go deep into the physics of skateboarding.

Physics Girl host, Hannah, begins the video by defining the three axis of movement the skateboard has. Long axis, mid-axis, and perpendicular axis. Hannah then makes the correlation between the shape of a skateboard and the shape of a phone in order to best describe the physics of an object shaped this way.

Flipping or moving your phone along this axis, you can imagine some tricks you might have seen performed by skaters. But try and flip the phone on its mid-axis and you’ll see where things get interesting. It is really difficult.

Try it with a book or something else with skateboard proportions and you’ll see it’s almost impossible to get this shape to flip consistently on this axis. Hanah then introduces us to the intermediate axis theorem. A theory that states any rotation of the intermediate axis is always unstable.

Hannah questions Mullen about skateboard tricks that move the board on this axis and Mullen admits there is really only one and, with the very suitable name of ‘the impossible.’ In fact, to do the trick, the skater needs to guide the board along that axis with their foot to avoid it spinning out of control.

So next time you head to the skatepark, take a moment to appreciate the physics behind every trick.

Via: Physics Girl