Index error while doing animation

I need help fixing this error to create the final adjustments of my animation for a school projuct error code is as follows and here is code as well.

Index exceeds the number of array elements (77).

Error in Group_Porject (line 67)

plot(t2(k2),z3(k2),'x')

clear all;  

close all;  

clc  

  

x0 = [0,0]; 

tspan = [0,6000]; 

[t1,x] = ode45(@f1,tspan,x0); 

[t2,y] = ode45(@f2,tspan,x0); 

z = x(:,1)/1609.34;

figure(1) 

plot(t1,z) 

ylabel('Horizontal Distance (mi)') 

  
z2 = x(:,2)*1.94384;
figure(2) 

plot(t1,z2) 

ylabel('Horizontal Velocity (kts)') 

  
z3 = y(:,1)*3.28084;
figure(3) 

plot(t2,z3)

ylabel('Vertical Distance ft)') 

  
z4 = y(:,2)*3.28084;
figure(4) 

plot(t2,z4) 

ylabel('Vertical Velocity (ft/s)') 

  
for k = 1:length(x)
    figure (5)
    plot(t1(k),z(k), 'x') 
    hold on
    plot(t1(k),z2(k),'x')
    plot(t1(1:k),z(1:k))
    hold on
    plot(t1(1:k),z2(1:k))
    axis ([0 6000 0 140])
    legend ('Horizontal Distance', 'Horizontal Velocity')
    pause(0.05)
    if k ~= length(t1)
        clf
    end
end
for k2 = 1:length(x)
    figure (6)
    plot(t2(k2),z3(k2),'x')
    hold on
    plot(t2(k2),z4(k2),'x')
    hold on
    plot(t2(1:k2),z3(1:k2))
    hold on
    plot(t2(1:k2),z4(1:k2))
    axis ([0 60000 0 2000000])
    pause(0.05)
    if k2 ~= length(t2)
        clf
    end
end
  

function dxdt = f1(t,x) 

    T = 1030; 

    if (x(1)>90*1609.34) 

        T=0; 

    end 

    m = 1000; 

    cd = 0.27; 

    dxdt(1,1) = x(2);  

    dxdt(2,1) = T/m-cd/m*x(2)^2; 

end 

  

function dydt = f2(t,y)  

    m = 1000;  

    W = m*9.81;  

    L = W + 50*exp(-.005*t); 

    dydt(1,1) = y(2);  

    dydt(2,1) = L/m-W/m; 

end 

[Star Strider]

The ‘z’ vectors are all defined by ‘y’ so incrementing by the length of ‘y’ will not throw the error:

for k2 = 1:length(y)
    figure (6)
    plot(t2(k2),z3(k2),'x')
    hold on
    plot(t2(k2),z4(k2),'x')
    hold on
    plot(t2(1:k2),z3(1:k2))
    hold on
    plot(t2(1:k2),z4(1:k2))
    axis ([0 60000 0 2000000])
    pause(0.05)
    if k2 ~= length(t2)
        clf
    end
end

The plot seems to not be consistent with the others.

.

[Robert Fields]

Awesome thank you with that I got it figured out.