I’ve started writing a piece about my own work, but in the meantime…EVERYONE LOVES A SLINKY!
A fella named Robert Hooke (who was a rival of Newton’s) formed a law about springs. The force that a spring will exert is proportional to how much you stretch it.
So when you release a slinky like this, the top has gravity and tension pulling it down. The bottom has tension pulling up and gravity pulling down so it doesn’t move. Incidentally, the spring is *always* falling. The centre of mass of the spring falls exactly as Newton would say it should.
Sidenote, in a letter to Hooke, Newton said “If I have seen further, it is by standing on the shoulder’s on giants.” That sounds noble as all hell (it’s written on British money) until you learn that Hooke was a poor-sighted short man.