function f19_2     %用數(shù)組制作動(dòng)畫,顯示時(shí)耗
close all
th=70*(pi/180);
g=32.2;s0=100;
tmax=2*s0*sin(th)/g;
xmax=xcoord(tmax,s0,th);
ymax=ycoord(tmax/2,s0,th,g);
w=linspace(0,tmax,500);
x=xcoord(w,s0,th);y=ycoord(w,s0,th,g);
plot(xcoord(w,s0,th),ycoord(w,s0,th,g)),hold,
h1=plot(xcoord(w,s0,th),ycoord(w,s0,th,g),'s','erasemode','xor');


%axis([0 xmax 0 1.1*ymax]),xlabel('x'),ylabel('y')
text(10,10,'time=');
time=text(30,10,'o','erasemode','background');
axis([0 xmax 0 1.1*ymax]),xlabel('x'),ylabel('y');
kmax=length(w);
for k=1:kmax
    set(h1,'xdata',x(k),'ydata',y(k))
    
    t_string=num2str(w(k));
    set(time,'string ',t_string);
    drawnow
    pause(0.001)
end
hold

function y=ycoord(t,s0,th,g);
y=-g*t.^2/2+s0*sin(th)*t;

function x=xcoord(t,s0,th);
x=s0*cos(th)*t;


%function y=ycoord(t,s0,th,g);
%x=-g*t.^2/2+s0*sin(th)*t;
%end
function v=vertvel(t,s0,th,g);
v=-g*t+s0*sin(th);