Mechanics

"What are you doing now Wu?"

"Ah, Kehr my boy, well I just wrote down my formulation of mechanics."

"Sorry sir, I ...."

"Oh sorry, well mechanics is the branch of physics, where we deal with the motion, and of course the cause of the movement. Well I am trying to reformulate the whole mechanics' principle. This is in fact something revolutionary, and ha, I think it is also ahead of my contemporary."

"Well can you show me? I will try to understand it.."

"Well you see, the old fashion way of seeing the nature of motion is limited, everything is governed by the force equation. F=ma. Mass times acceleration. Simple and elegant, it was, but until when you have lots of system to be considered. Like for instance, we would like to take three candy and throw them around, and see how they react."

"Candies can react among each other?"

"Well sort of bad example is it not? Ha, well remember this, a new way of looking into difficult question, the least action principle. It makes everything look easy. All you need is the kinetic energy minus the potential energy of the body that you want to observe. Voila, the equation of motion comes from a simple derivative."

"I think I am lost, but yes I do believe if we have the least action principle, we should get something simple in nature, is it not? Like the fastest way to go along the street is "to move along it", straight and no deviation."

"Brilliant, as simple as that, but do remember, the simple geometry that you believe as intuition is sometimes not correct. A plane is not a plane anymore when we view from "outside", right?"

"Like looking at a piece of paper from our eyes?"

"Ha Ha, indeed. Fold the paper and you have the zero distance."