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!

Escape nelocity derivation

  1. Feb 28, 2006 #1
    escape velocity derivation

    The problem is thus:
    The acceleration of a satellite is given by -gR^2/r^2 where R= radius of earth and r = distance of satellite from center of the earth. Find escape velocity.

    Now I have read the solution to this problem and in it the author at one point has integrated v dv = -gR^2/r^2 with the upper limit for vdv being 0 and the lower limit being Ve(Escape velocity).

    Now my problem is, why is 0 the upper limit and Ve the lower limit if in magnitude Ve>0?
    Last edited: Feb 28, 2006
  2. jcsd
  3. Feb 28, 2006 #2
    Think of it this way: the escape velocity is the bare minimum velocity needed to always move away from the planet, so you could say that "at infinity" (which is a strange concept, let's just say "very far away") the satelite's velocity is "zero" (really close to zero). Thus the satelite starts out near the Earth at the escape velocity Ve and ends up out at infinity with zero velocity.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Threads - Escape nelocity derivation Date
Deriving the Biot Savart Law Wednesday at 11:59 AM
Escapement in a clock Mar 13, 2018
Angle of escaping electric field lines Jan 27, 2018
Electron Escape Speed Dec 3, 2017
An object is launched from the Earth to escape the Sun Dec 2, 2017