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!

Particle pierces a sphere (vector)

  1. Dec 3, 2006 #1
    A particle starts from point (-2,1,2) with velocity vector v = < 1,1,0 > and hits the plane x + z = 2 and bounces off and penetrates through a sphere x² + y² + z² = 25 at two points, P and Q. What is the angle between OP and OQ.

    This was a question on one of my exams that I did not get. I cannot remember completely, but I think the OP and OQ are vectors sharing the origin of the coordinate system as their vertex and we want to find that angle between them.

    So I am trying to work this one out and I am getting really stuck.

    I started by parametrizing the starting point and vector and came up with:

    x = -2 + t
    y = 1 + t
    z = 2

    where t = 2

    I also know that the angle of incidence will = the angle of reflectance, so v = -u = < -1,1,0 > (is this statement true?)

    But I don't see how I can relate this to the angle between P and Q
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you help with the solution or looking for help too?