My plot is not showing a line?

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);

[the cyclist]

Unrecognized function or variable 'Time'.

Error in answerTest (line 16)

S=d1/Time;

========================

Should Time have been t?

[Andrei Sacal]

sorry, change "Time" to t

Answer 1

[the cyclist]

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.

[Andrei Sacal]

can you check this one please im trying to get it to plot a line

%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(0,s1p);

[the cyclist]

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])