pend.m

matlab程序

% 单摆的动态演示   (pend.m)

% 挂摆横梁
clf
plot([-0.2;0.2],[0;0],'color','y','linestyle','-',...
'linewidth',10);
%画初始位置的单摆
g=9.8;
l=1;
theta0=pi/6;  x0=l*sin(theta0);
y0=-l*cos(theta0);
axis([-0.75,0.75,-1.25,0]);
axis('off');	%不显示坐标轴
% 创建摆锤

 head = line( ...
        'color','r', ...
        'Marker','.', ...
        'markersize',25, ...
        'erase','xor', ...
        'xdata',x0,'ydata',y0);



axis('off');	%不显示坐标轴
%创建摆杆
body=line([0;x0],[0;y0]);
% 摆的运动
t=0;
dt=0.005
while 1
	t=t+dt;
	theta=theta0*cos(sqrt(g/l)*t);
	x=l*sin(theta);
	y=-l*cos(theta);
	set(head,'xdata',x,'ydata',y);
	set(body,'xdata',[0;x],'ydata',[0;y]);
	drawnow;
end