1. Not finding help here? Sign up for a free 30min 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!

Another Vectors Question.

  1. Apr 22, 2006 #1
    Two ships P and Q are travelling at night with constant velocities. At midnight, P is at the point with position vector (20i + 10j) km relative to a fixed origin O. At the same time, Q is at the point with position vector (14i – 6j) km. Three hours later, P is at the point with position vector (29i + 34j) km. The ship Q travels with velocity 12j km h–1. At time t hours after midnight, the position vectors of P and Q are p km and q km respectively. Find
    (a) the velocity of P, in terms of i and j,

    (b) expressions for p and q, in terms of t, i and j.

    At time t hours after midnight, the distance between P and Q is d km.
    (c) By finding an expression for PQ, show that
    d^2 = 25t^2 – 92t + 29^2.
    ---

    Hi... another vectors question....
    i get the answers to part a and and b... however, for C i dont really know how to do this one.... maybe im lacking the principles to this question. :confused: ... If anyone could walk me through part C.. it would really help...
    Thanks :)

    PS. Do you know of any good internet source that has extensive tutorials on vectors?
     
  2. jcsd
  3. Apr 22, 2006 #2

    Hootenanny

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    How'd you calculate the distance between two points on a graph? You should apply the same rule here.

    ~H
     
  4. Apr 22, 2006 #3
    (y2 -y1) ÷ (x2 -x1)?
     
  5. Apr 22, 2006 #4

    Hootenanny

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Using pythag;

    [tex]d = \sqrt{(x_{2}-x_{1})^2 + (y_{2}-y_{1})^2}[/tex]

    ~H
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Another Vectors Question.
  1. Another Vector Question (Replies: 11)

Loading...