From: Ashley Butterworth <macbse@...>

Date: Thu, 27 Jun 2002 13:42:10 +1000

Date: Thu, 27 Jun 2002 13:42:10 +1000

On Thursday, June 27, 2002, at 12:57 PM, Peter Bancroft wrote: >> Can any of you geniuses provide an outline for creating a particle >> spewer? >> >> >> Particle goes up, perhaps with some angular vector amount toward one >> side >> or another , thus arcs over due to gravity, falls, then bounces a >> couple >> times..not big bounces...like a Sparkler. > > Sinusoids with a gravity component. Look for the mathematics of > trajectories of cannon balls or bullets. > > Peter > Year 11 physics actually. They are actually parabolas. You break it into the x and y components. X acceleration = 0 Y acceleration = -g (positive is up) X velocity = k (constant (given by x component of the launch velocity)) Y velocity = -gt + C1 (integrate acceleration with respect to time) work out constant with initial conditions (t = 0, Y velocity = y component of launch velocity). X position = kt + C2 (integrate velocity with respect to time) work out constant with initial conditions (position relative to origin at t = 0) Y position = (-g/2)*(t^2) + C1t + C3 (integrate velocity with respect to time) work out constant with initial conditions (position relative to origin at t = 0) If there is acceleration in the x direction then you need to start with that and integrate up to the position. if you want X,Y coordinates you eliminate t in the position equations. Hope this helps Ashley ~)~ ======================================================== Ashley Butterworth Email: macbse@... ======================================================== _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com