Haalp, o physics geeks on the flist

[snowgrouse]

HAAALP. What's the name for that point where a pendulum reaches the end of its trajectory, when it's swung as high as it can go before it starts moving back? I was reading Wikipedia on it and scratching my head. They talk about the "moment of inertia", but apparently that can also mean the movement itself if it just keeps doing the exact same thing

Comments

[snowgrouse]

That's interesting, actually... but bah, might have to scratch the whole metaphor, it was getting convoluted anyway.

[jhall1]

All I can recall from physics lessons from forty years ago is that the motion of a pendulum obeys "simple harmonic motion". I just looked that term up on Wikipedia, but I don't think that it helps at all.

Ah, just thought of something. Isn't the term that you are looking for "stationary point"? (So-called because the pendulum is motionless there for an infinitisemal instant.)

[abates]

The apex of its swing, perhaps?

[snowgrouse]

I looked up apex and it seems to be restricted to pyramids or triangles? GAH.

[alryssa]

Not sure if zenith would serve the purpose you're looking for...

[snowgrouse]

Oooh. Thanks. Will look into it.

[astrogirl2]

I think "the end of its trajectory" is fine, actually. Terms like "apogee," "apex" and "critical point," however, are kind of wrong. Especially "apogee." :)

To be honest, I don't actually remember calling it anything back when I was studying this stuff. I think we usually just described it with equations. :)

[snowgrouse]

Thank you! That helps muchly.

[astrogirl2]

It might not bother most people when used metaphorically, but in this case it definitely reads as wrong to me, and would very possibly ping my "wait, this person doesn't actually know what they're talking about" detector and throw me out of the story. *shrug* "Apogee" is a technical term. It is, indeed, the point of highest potential energy, but it's not the term for any point of highest potential energy, only that of an object in orbit around the Earth. (Technically, it's not even the correct term if you're orbiting something other than Earth.)

"End of its trajectory" isn't exactly scientifically precise, but it doesn't ping my "misuse of a technical term" detectors in the same way.

Other space geeks' mileage may vary, of course. :)

Anyway, there are lots of ways to describe that particular point, it's just that I can't think of any that aren't pretty clunky and non-poetic. "Point of maximum displacement," for example.

[astrogirl2]

And, actually, "turning point" is probably OK, too, if that works for ya.

[snowgrouse]

Ooh, that's interesting and simple. Again, I might just chicken out and work around the term somehow, just say "the pendulum will swing again" or something lame like that. I'd rather go for more vague terms than risk looking like a complete ignorant idiot...