Re: Language Challenge 2000

[Vincent DIEMUNSCH <vincent.diemunsch@edf.fr>]

I have a few questions regarding the equations themselves :


>Find the optimal initial angle for a trajectory to reach a target at
>000 m to within .5 m. The equations of motion are given by,
>
>               mx" + Dcos(alfa) = 0
>                my" + Dsin(alfa) + mg = 0
>where
 >               D = .5*Cd*A*rho(y)*v^2     alfa = atan(y'/x')
>
>and rho() is a variable atmospheric density w.r.t. altitude.
>
>Parameters:     m = 20 kg   Cd = .3   A = .02 m^2   g = 9.80665 m/s^2
>Initial values: x = 0 m    y = 0 m   v = 180 m/s   alfa = 40 deg

- What is the rho(y) function exactly ?
- shoudn't it be my" + Dsin(alfa) - mg = 0   instead of  my" + Dsin(alfa) +
mg = 0 ?

And finally cos(atan(y'/x')) = x'/v and sin(atan(y'/x')) = y'/v, which will
certainly speed up computing !!!




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