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!

Kinetic energy of N solid bodies

  1. May 13, 2010 #1

    Oddbio

    User Avatar
    Gold Member

    This is a fairly simple question so I wasn't sure if it belongs here, but it is not a homework question. Just a question on something I'm reading.

    The book says there are N solid bodies with initial speed vi (i=1, 2, 3, ..., N)
    and final speed vi' after some shock to the system.

    The book then says that the difference in kinetic energy is:
    [tex]\sum_{i=1}^{N}m_{i}(v_{i}'^{2}-v_{i}^{2})[/tex]

    But my question is, where did the (1/2) factor go from the kinetic energy?

    I was even wondering if this has something to do with combining the sum for initial and final kinetic energies into a single script, but if I write the sum out using "j" for initial and "i" for final in the sums it comes out to be what they have but with a (1/2)... like I think it should.
    Am I supposed to assume that this is just a typo? Even though several calculations are performed from that equation following its appearance.
    I can't see any reason why it would be missing.
     
  2. jcsd
  3. May 14, 2010 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Hi Oddbio! :smile:
    Typo (or laziness of the author)! :rolleyes:

    I assume that it makes no difference to the calculations because it's missing from both sides of every equation.

    But the author still shouldn't leave it out without warning. :frown:
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Kinetic energy of N solid bodies
  1. N body problem help (Replies: 1)

Loading...