MATLAB: Subscript indices error when plotting

Question

I am having an issue with a for loop plot. The error is returned on the line that says "plot(x,y)" on the code which follows. It states "Subscript indices must either be real positive integers or logicals." Also, if there is any way to label the plots in a legend as they are created that would be great. Thanks in advance for any help.

 for N=30:10:50
 g=9.81;tau = 0.0076;
 tmin = 0; tmax = 10;
 v0=50*sin(deg2rad(N));y0=0;
 t=linspace(tmin,tmax, 1000);
 dt=t(2)-t(1);
 a= zeros(1,numel(t));
 v= zeros(1,numel(t));
 y= zeros(1,numel(t));
 v(1)=v0;
 y(1)=y0;
 for i=2:1000
     a(i-1)= -g+(tau*abs(v(i-1))*v(i-1)); 
     v(i)= v(i-1)+a(i-1)*dt;
     y(i)= y(i-1)+v(i-1)*dt+(1/2)*a(i-1)*dt^2;
 end
 vx0=50*cos(deg2rad(N));x0=0;
 ax= zeros(1,numel(t));
 vx= zeros(1,numel(t));
 x= zeros(1,numel(t));
 vx(1)=vx0;
 x(1)=x0;
 for i=2:1000
     ax(i-1)= -tau*(vx(i-1))^2; 
     vx(i)= vx(i-1)+ax(i-1)*dt;
     x(i)= x(i-1)+vx(i-1)*dt+(1/2)*ax(i-1)*dt^2;
 end
 plot(x,y);
 ylim([0,65]);
 end

Answer 1

In some code not shown here, you accidentally assigned a value to a variable named plot