Compound Pendulum

[John T]

Hi Art
Just a clarification for me please  In calculating a compound pendulum - when the calculator says the small m (arm) is 0.75 Is that both sides combined or is it on each side?

John

[ArtF]

John:

  Its the ratio of distance to one sides distance. So it your main distance is 20 inches, .5 would be 10 inches per side.

Art

[John T]

Hi Art
Actually I was asking about the weights on the ends of the arms

The arm length is in the "calculator" isn't it?

John

[ArtF]

John:

My apologies, I hadn't used it for awhile and my mental image was weak. Your quite correct,
the weights are the ratio, so its the ratio fo the weight of the main bob, and it is for each side.

Art

[John T]

Hi Art,
I'm a little confused by the little screen that calculates the compound pendulum.

If I keep all the variables constant except "L" I would expect that lengthening L would have a predictable effect, but when I try this I find that lengthening will make the period longer, however shortening L also makes the period longer.  Is this correct?

[ArtF]

John:

Doesnt sound right, Ill check the math on it and get back to you..

Art

[ArtF]

John:

Doesnt seem to repeat here, shortening L makes it faster, lengthening makes it slower.. as Id expect.
Does it do this with any angle selected?

Art