Posts Tagged ‘Martial Arts’
Momentum and Martial Arts
Posted on: January 7, 2009
There is no easy way to demonstrate this in writing, so I will be brief. (Maybe I’ll video this at the gym tomorrow night and post it here.)
A key to martial arts is using an attackers momentum against himself. We don’t want to use direct force against an attack when a small redirecting force creates so much more havoc.
The move I have in mind is when an attacker is swinging a sucker punch or roundhouse punch. By blocking and pulling on both the punching arm and neck of the attacker, you can send them down to the floor. ( I don’t recommend this to those without some serious martial arts training.)
The physics here is all about impulse. My effort is minimal, I use a very small force to add to their momentum and throw the attacker off balance.
Yeah, like I said, I need to make a video of this one.
This is much harder to write than to show. The physics books usually have a problem about the tension in a horizontal cloths line with a single force hanging down in the middle. We can calculate these forces fairly easily, but hands on is better. The outdoor demonstration is to tie a strong rope between a tree and a car, then moving the car by applying a perpendicular force on the rope at the midpoint.
There is an even more effective demonstration of this that can be done in the classroom. It’s a martial arts escape from two attackers. I like to pick the two strongest and largest students as my victims. They each grab one of my wrists and pull away from each other. (They think they are so tough.) I then take a big step backwards and pull my hands towards each other. The two attackers move towards each other with a great deal of force and almost always bump into each other with surprising speed and force.
Physics & Physical Science Demos, Labs, & Projects for High School Teachers 
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