[futurebasic] Re: [FB] Trajectory stuff

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From: Ashley Butterworth <macbse@...>
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@...
========================================================


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