Re: Aikido is all about "Engineering and Physic's"
The human brain is an amazing "physics computer". Whether or not the person doing a movement consciously understands anything about physics, any movement we generate ends up being about the physics of it.
Imagine the baseball outfielder - or the cricket fielder - the ball is struck, it's on a high parabolic arc which is influenced by gravity, air resistance, wind direction, and the spin of the ball as it leaves the bat. Without a moment's pause to calculate anything, the fielder can run to where the ball is going to land so that he or she can catch the ball. Imagine writing up the equation for that...
The aikido person does all that computation inside, also, without realizing it. As others have commented it, some call it physics (which I think about to speed up how I learn something, until I don't have to think that way and I can do it by feel), others call it "ki".
It's not simple. When starting out in biomechanics I was shown a film (yes, a 16 mm film, it's that long ago) of the steps to "optimize" something as simple as a kick to a target. I can't remember the details but it took something like 30 variables, (a lot of) ordinary differential equations, and 24 hours of computing time in a PDP-11 (what used to be a really good computer, probably trashed by a pentium processor for processing power) to calculate an "optimal" strategy for a person to kick a target that was at waist height..
Calculations we're not aware of - neural transmission rate, muscle recruitment patterns, "think" time, sensory-to-spine-to-brain-to-processing-to-forming-a-response-plan-to-sending-the-signal-to-nerve-transmission-to-spine-to-muscle-to-contract-to-movement. Studies have shown that if you've started a response, and you need to make a change, there's a gap of (here's my forgetting... is it 150 milliseconds?) during which you can't even start a change. An example is the goaltender in ice-hockey - sees a shot coming, starts to move to catch the puck, but his team-mate's leg deflects the path of the puck in the last metre of the puck's flight to where the goalie thinks the puck is going, and suddenly the puck is no longer going there - sorry - you don't have time to reprogram the response, and the puck is in the net.
It's physics, and chemistry, and.... magic?