From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=0.1 required=5.0 tests=BAYES_05,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,88a843cdd1eb738a X-Google-Attributes: gid103376,public From: Vincent DIEMUNSCH Subject: Re: Language Challenge 2000 Date: 2000/02/04 Message-ID: <389A89BF.123B8112@edf.fr>#1/1 X-Deja-AN: 581440029 Content-Transfer-Encoding: 7bit References: <38964D82.3423805@sdynamix.com> X-Accept-Language: fr Content-Type: text/plain; charset=us-ascii X-Complaints-To: newsadm@news.edf.fr X-Trace: clnews.edf.fr 949651904 20787 144.165.69.25 (4 Feb 2000 08:11:44 GMT) Organization: Direction des Etudes et Recherches EDF Mime-Version: 1.0 NNTP-Posting-Date: 4 Feb 2000 08:11:44 GMT Newsgroups: comp.lang.ada Date: 2000-02-04T08:11:44+00:00 List-Id: 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 !!! > > > ----------------------------------------------- > Modeling * Simulation * Analysis > http://www.sdynamix.com > -----------------------------------------------