My plot is not showing a line?

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Andrei Sacal on 22 Nov 2021
Answered: VBBV on 23 Nov 2021
can you please take a look at the following code and let me know why my plot isn't showing a line?
my plot is coming out blank, Im trying to get a graph that looks like this %constants
d1 = 28;
d2 = d1;
m = 2;
F = 10;
Vmax = 3;
nVmax = -3;
%acceleration
a=F/m;
%Time
t=d1/Vmax;
%speed
S=d1/Time;
% Graph to show velocity of cart at 10 intervals
T=0:t/10:t;
%velocity
v=a*T;
x=T;
na = a - a*2; %deceleration
t1 = Vmax/a;
t2 = nVmax/na;
s1 = (1/2)*(((Vmax)*(Vmax))/a);
s2 = (Vmax)*(t2)+((1/2)*(na)*((t2)*(t2)));
tm = t - (t1+t2);
St1 = t1 + (1/2)*(tm);
St2 = t2 + (1/2)*(tm);
plot(t1,s1);
hold on
plot(tm, Vmax);
hold on
plot(t2, s2);
hold on
plot(S,t2);
Andrei Sacal on 22 Nov 2021
sorry, change "Time" to t

the cyclist on 22 Nov 2021
Edited: the cyclist on 22 Nov 2021
Here is a modified version of your code, where I changed Time to t (in the assignment of S), and I plotted your data as large individual points:
%constants
d1 = 28;
d2 = d1;
m = 2;
F = 10;
Vmax = 3;
nVmax = -3;
%acceleration
a=F/m;
%Time
t=d1/Vmax;
%speed
S=d1/t;
% Graph to show velocity of cart at 10 intervals
T=0:t/10:t;
%velocity
v=a*T;
x=T;
na = a - a*2; %deceleration
t1 = Vmax/a;
t2 = nVmax/na;
s1 = (1/2)*(((Vmax)*(Vmax))/a);
s2 = (Vmax)*(t2)+((1/2)*(na)*((t2)*(t2)));
tm = t - (t1+t2);
St1 = t1 + (1/2)*(tm);
St2 = t2 + (1/2)*(tm);
figure
hold on
h(1) = plot(t1,s1,'.');
h(2) = plot(tm, Vmax,'.');
h(3) = plot(t2, s2,'.');
h(4) = plot(S,t2,'.');
set(h,'MarkerSize',32) You can see that each plot was only a single point. So, when you try to plot a line "between the points", nothing shows up because there are no lines to draw.
the cyclist on 22 Nov 2021
Your plotting, when we substitute in the value of s1p, is
plot(0, [0.6 3]) is has syntax, but doesn't really make sense. You need to pair and equal number of x and y points. Like this:
plot([0 0], [0.6 3]) VBBV on 23 Nov 2021
%constants
d1 = 28;
d2 = d1;
m = 2;
F = 10;
Vmax = 3;
nVmax = -3;
%acceleration
a=F/m;
%Time
t=d1/Vmax;
%speed
S=d1/t;
% Graph to show velocity of cart at 10 intervals
T=0:t/10:t;
%velocity
v=a*T;
x=T;
na = a - a*2; %deceleration
t1 = Vmax/a;
t2 = nVmax/na;
s1 = (1/2)*(((Vmax)*(Vmax))/a);
s1p = [t1, Vmax];
tm = t - (t1+t2);
s2 = (Vmax)*(t2)+((1/2)*(na)*((t2)*(t2)));
tv = t1+tm;
s2p = [tv, Vmax];
St1 = t1 + (1/2)*(tm);
St2 = t2 + (1/2)*(tm);
plot(s1p); hold on; plot(s2p) you can try this