小球以v=30m/s从地面跳起，落地弹起后v为原来90%，用MATLAB编程建立动态模型及运动轨迹

clear
v0=30;g=-9.8;
dt=0.05;
t=0:dt:80;
[n1,n2]=size(t);
i=1;
v=zeros(n1,n2);
s=zeros(n1,n2);
for i=1:n2
if i==1
v(1)=v0;
s(1)=0;
else
v(i)=v(i-1)+g*dt;
s(i)=s(i-1)+v(i-1)*dt+1/2*g*dt^2;
end
i=i+1;
if (v(i-1)<0)&&(s(i-1)<=0)
v(i)=-0.9*v(i-1);
end
end
x=zeros(n1,n2);
rt=0:0.2:2*pi;
r=2;
for i=1:n2
plot(x(i)-r.*cos(rt),s(i)-r.*sin(rt)+r,'r')
axis([-30 30 0 50])
drawnow
end

的撒旦撒