I was at the gym earlier today. When I got out of the shower and was opening my locker, a book (“Crack Climbing”) fell out. I marveled over the sequence of my reaction. Earth’s gravity is the weakest of the four fundamental forces, but it still makes stuff fall impressively fast.
I didn’t move my foot when the book fell, and after I had picked it up I thought about what must have happened in the < 1 second that it took for the book to fall:
- Hey! Something’s falling.
- It might hit me.
- Identification of falling object: It’s a book.
- Is it going to hit me? Maybe.
- Okay, it’s not too hefty.
- What have my past experiences been with things like this? Not too bad.
- Conclusion: No need to quickly move my foot out of the way.