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!

Motion of objects collide

  1. Jun 28, 2009 #1
    Hello all ^^

    I have two objects moving in 2d space, their positions given by:

    x1 = r1*cos(s1 * time)
    y1 = r1*sin(s1 * time)


    x2 = r2*cos(s2 * time)
    y2 = r2*sin(s2 * time)

    Essentially, I want to see if they collide or exist in the same place at any time. So I am guessing I need to solve twice for both x and y collisions.

    I did this, but am stuck isolating time (or solving the problem :P)....

    r1*cos(s1 * time) = r2*cos(s2 * time)

    I am trying to isolate the time they collide (if they do)...

    I am not too good at maths, and the answer is probably really simple, but any help is greatly appreciated! This is not homework, its for a hobby computer game I am trying to make.

  2. jcsd
  3. Jun 28, 2009 #2


    User Avatar
    Science Advisor
    Homework Helper

    Hello Adrian! :smile:

    These are circles, with radius r1 and r2, respectively, and both centred at the origin (0,0).

    So the objects won't collide unless r1 = r2 :wink:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook