Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Shortest distance

  1. Oct 2, 2009 #1
    What will be the shortest point on the opposite "vertices" of a cylinder?

    Attached Files:

  2. jcsd
  3. Oct 2, 2009 #2
    Do you mean the shortest PATH along the surface of the cylinder?

    I imagine if you parametrize points by angle and height, plot your start and end points on a the plane, draw a straight line between them, and then translate those to the points on the surface to take the length.

    At least, that'd be my starting point. You have to consider that angle-height coordinates aren't unique. When you plot the points, you need to plot one twice. One at one angle and one 360ยบ less. You draw two paths and pick the shortest.

    Then you'd have to prove it. I'm not sure how you'd do that, but it seems obvious enough.
  4. Oct 2, 2009 #3


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Cut the cylinder vertically and unroll it to a rectangle. Draw the straight line between the points (having cut it so that can be done). Take its length.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook