Results 1 to 3 of 3

Thread: Moon

  1. #1
    Platinum Lounger
    Join Date
    Feb 2002
    Location
    A Magic Forest in Deepest, Darkest Kent
    Posts
    5,681
    Thanks
    0
    Thanked 1 Time in 1 Post

    Moon

    Jezza Bear had just polished of the last mince pie and was sitting in the porch gazing at the waning moon. "I must ask Al Bear how to work out the perimeter of the waning moon"

    Assuming that we are talking about a 2 dimensional crescent with arbitary radius r what is the perimeter length of the shape below?
    Jerry

  2. #2
    Star Lounger
    Join Date
    Jul 2006
    Location
    Colorado, USA
    Posts
    55
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: Moon

    Just to make sure, are we talking about a circular arc on the left and an elliptical arc on the right (both start and end at north and south pole) or two overlapping circular arcs of same size? The real thing would have a circular arc on the left and an elliptical arc on the right, otherwise it would not be able to progress to a straight line at the quarter phases. The answer would require messy elliptical integrals. If you are talking about two circular arcs, the answer would be 2*pi*r.

  3. #3
    Platinum Lounger
    Join Date
    Feb 2002
    Location
    A Magic Forest in Deepest, Darkest Kent
    Posts
    5,681
    Thanks
    0
    Thanked 1 Time in 1 Post

    Re: Moon

    Your assumption is correct as is your answer have a [mince pie]
    Jerry

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •