That's why I came to sciforums. I wanted to get educated thoughts on the matter, and it taught me to get back into the subject (review the books again) before speaking, and mostly answer my own questions, as much as possible, before asking up the chain. Old age I guess.
Kinetic energy is typically energy associated with the speed of something. All photons travel at the speed of light, but clearly their energies can vary. Therefore, describing photon energy as "kinetic" seems like it might be a mistake, to me.
Nothing! No force is required for something to travel at a constant velocity.
Idiot.
Lots of things act on the car to slow it down, such as rolling friction between the tyres and the road and air resistance.
For those who prefer words rather than wading through videos, what is needed is a process that generates a pair of photons from a single quantum emission event. This can be done with certain "non-linear" materials, in which excitation by a single input photon results in emission of a pair of photons rather than just one as normally expected. More here: https://en.wikipedia.org/wiki/Spontaneous_parametric_down-conversion
The advantage of written words is efficiency in communicating.
That is, and has always been, bullshit. A picture is useful to accompany words. Without those it can be anything at all, or nothing. And a video is not a picture. It is some guy rambling on, at a speed you cannot control, in a linear fashion, so you are trapped into going at his pace and cannot easily focus on the points you want to. Video is usually dreadful.
