"Ричард Фейнман. Surely You're Joking, Mr. Feynman!/Вы, конечно, шутите, мистер Фейнман! (англ.)" - читать интересную книгу автора

clock is as far ahead as possible. According to Einstein, if you go very
high, your clock will go faster, because the higher something is in a
gravitational field, the faster its clock goes. But if you try to go too
high, since you've only got an hour, you have to go so fast to get there
that the speed slows your clock down. So you can't go too high. The question
is, exactly what program of speed and height should you make so that you get
the maximum time on your clock?
This assistant of Einstein worked on it for quite a bit before he
realized that the answer is the real motion of matter. If you shoot
something up in a normal way, so that the time it takes the shell to go up
and come down is an hour, that's the correct motion. It's the fundamental
principle of Einstein's gravity - that is, what's called the "proper time"
is at a maximum for the actual curve. But when I put it to him, about a
rocket with a clock, he didn't recognize it. It was just like the guys in
mechanical drawing class, but this time it wasn't dumb freshmen. So this
kind of fragility is, in fact, fairly common, even with more learned people.

When I was a junior or senior I used to eat at a certain restaurant in
Boston. I went there by myself, often on successive evenings. People got to
know me, and I had the same waitress all the time.
I noticed that they were always in a hurry, rushing around, so one day,
just for fun, I left my tip, which was usually ten cents (normal for those
days), in two nickels, under two glasses: I filled each glass to the very
top, dropped a nickel in, and with a card over it, turned it over so it was
upside down on the table. Then I slipped out the card (no water leaks out
because no air can come in - the rim is too close to the table for that).
I put the tip under two glasses because I knew they were always in a
hurry. If the tip was a dime in one glass, the waitress, in her haste to get
the table ready for the next customer, would pick up the glass, the water
would spill out, and that would be the end of it. But after she does that
with the first glass, what the hell is she going to do with the second one?
She can't just have the nerve to lift it up now!
On the way out I said to my waitress, "Be careful, Sue. There's
something funny about the glasses you gave me - they're filled in on the
top, and there's a hole on the bottom!"
The next day I came back, and I had a new waitress. My regular waitress
wouldn't have anything to do with me. "Sue's very angry at you," my new
waitress said. "After she picked up the first glass and water went all over
the place, she called the boss out. They studied it a little bit, but they
couldn't spend all day figuring out what to do, so they finally picked up
the other one, and water went out again, all over the floor. It was a
terrible mess; Sue slipped later in the water. They're all mad at you."
I laughed.
She said, "It's not funny! How would you like it if someone did that to
you - what would you do?"
"I'd get a soup plate and then slide the glass very carefully over to
the edge of the table, and let the water run into the soup plate - it
doesn't have to run onto the floor. Then I'd take the nickel out."
"Oh, that's a goood idea," she said.
That evening I left my tip under a coffee cup, which I left upside down