1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Help with distance between cities?

  1. Feb 26, 2012 #1
    1. The problem statement, all variables and given/known data
    Find the distance in kilometers between each pair of cities assuming they lie on the same north-south line:
    Panama City, Panama, 9° N and Pittsburgh, Pennsylvania 40° N


    2. Relevant equations
    All we talked about in class is that θ = S/r


    3. The attempt at a solution
    I'm really not sure what to do... I assume I'm supposed to be solving for s or r, given that θ1 is 9 and θ2 is 40 but...I'm still not sure what to do.
     
  2. jcsd
  3. Feb 26, 2012 #2

    PeterO

    User Avatar
    Homework Helper

    The distance between them is along an arc - if you assume the earth is a perfect sphere - we commonly do.
     
  4. Feb 26, 2012 #3
    So what am I supposed to do? All I'm given is 9 and 40. I know I need S or R, but I don't know how to get them.
     
  5. Feb 26, 2012 #4
    Nevermind, I think I've got it. Apparently the radius of Earth is 6400 km. So I converted the given θ's to radians and then solved for S for the both of them, then subtracted to get the distance between the two :D Thanks for the hint, PeterO
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook