I think You understand that I don't put the best copies of my textbooks on the site.
The depth of knowledge has already become so great that I see the first experimental model of a fuel-free airplane engine, similar to the one that moves a photon at the speed of light 300,000 km/s. It turns out that its speed can be different. I took this as a hint from God to say goodbye to science. The site will continue to work contactless with readers of my SCIENTIFIC and EDUCATIONAL SITE.
27.07.2020. K. F. M.