compli_ball.m

matlab宝典,电子工业出版社,包含该书的源码12-14章

function Compli_ball
% Script file ball.m
%
% Purpose:
%    This program calculates the distance traveled by a ball
%  thrown at a specified angle "theta" and a specified velocity
%  "vo" form a point,ignoring air friction .It calculates the angle
%  yeilding maximum range,and also plots selected trajectories.
%
% Define variables:
%   conv      degrees to radians conv factor
%   grav      The gravity accel
%   ii,jj     Loop index
%   index     The maximum range in array
%   maxangle  The angle that gives the maximum range
%   maxrange  Maximum range 
%   range     range for a specified angle
%   time      Time
%   theta     Initial angle
%   fly_time  the total trajectory time
%   vo        The initial velocity
%   vxo       x-component of the initial velocity
%   vyo       y-component of the initial velocity
%   x         x-position of ball
%   y         y-position of ball

%  Constants
conv=pi/180;
grav=-9.82;
vo=45;

range=zeros(1,91);

% Calculate maximum ranges
for ii=1:91
     theta=ii-1;
     vxo=vo*cos(theta*conv);
     vyo=vo*sin(theta*conv);
     max_time=-2*vyo/grav;
     range(ii)=vxo*max_time;
end

%Write out table of ranges
fprintf('Range versus angle theta:\n');
for ii=1:5:91
    theta=ii-1;
    fprintf('%2d %8.4f\n',theta,range(ii));
end

% Calculate the maximum range and angle
[maxrange index]=max(range);
maxangle=index-1;
fprintf('\n Max range is %8.4f at %2d degrees.\n',maxrange,maxangle);