Matlab graph is not drawn

I was trying to plot a x vs t graph of vertical projectile motion until the maximum altitude with the following code but the graph is not plotted. What can be the problem?

V0=1000 + 100*7 + 50*8;
x(2)=0;
t0=0;
R=6.37*10^6; 
g0=9.81;
dt=100;
k=2;
for i=0:dt:1000
    if x(k)>x(k-1)
        g=g0*R^2/(R+x(t))^2;
        x(k+1)= 2*x(k)-x(k-1)+g*dt^2;
    end
end
plot(t,x)

Answer 1

[Les Beckham]

You aren't incrementing k or creating t in your loop.

There are also other things wrong with your calculation of x. For one thing, I don't see that you are using V0 at all.

Try something like this to get a plot and then fix your calculations to get a plot that actually looks like what you expect.

V0 = 1000 + 100*7 + 50*8;
% x(2)=0;
% t0=0;
R = 6.37*10^6; 
g0 = 9.81;
dt = 100;
% k=2;
t = 0:dt:1000;
x = zeros(size(t));
for k=2:numel(t)
    if x(k)>x(k-1)
        g = g0*R^2/(R+x(k))^2;
        x(k+1)= 2*x(k) - x(k-1) + g*dt^2;
    end
end
plot(t,x)