How do i Plot average velocity from given velocity time data?

Below is the given question. I am not able to plot the below underlined part of the question.

Determine the distance traveled from a velocity function v(t) where the velocity is

explicitly given at the following time points:

t= [1 2 3.25 4.5 6 7 8 8.5 9 10];

v= [5 6 5.5 7 8.5 8 6 7 7 5];

Use the trapezoidal rule. In addition, determine the average velocity

Display in a figure with 2 subplots

• in the upper subplot showing the traveled distance over time as a black solid line,

• in the lower subplot showing the velocity data over time as a blue solid line and the

average velocity as a red dashed line over the time range

• with the corresponding titles, labels of the axes and legend (containing the average

velocity value).

t= [1 2 3.25 4.5 6 7 8 8.5 9 10];
v= [5 6 5.5 7 8.5 8 6 7 7 5];
d=trapz(t,v);
disp("Distance Travelled= "+d);

Distance Travelled= 60.125

D=cumtrapz(t,v);
Vavg=(D(10)-D(1))/(t(10)-t(1));
disp("Average velocity= "+Vavg);

Average velocity= 6.6806

subplot(2,1,1)
plot(t,D,'k');
xlabel("Distance");
ylabel("Time")
title("Travelled Distance over Time");

subplot(2,1,2)
plot(t,v,'b',"DisplayName"," velocity");
hold on
plot(t,Vavg,'r',"DisplayName","Avg Velocity");
hold off

Answer 1

[Dave B]

You were very close, you don't see it because you've plotted a vector t against a scalar Vavg and MATLAB has interpreted this as creating 10 points (but there's no marker, so it's 10 lines each having no x or y span, so they're infinitely small and you can't see them).

plot(t([1 end]),[Vavg Vavg],'r',"DisplayName","Avg Velocity");

Or you can take the modern MATLAB approach and use yline:

yline(Vavg,'r',"DisplayName","Avg Velocity")

[Samson David Puthenpeedika]

oh Yes thankyou . I was little confused thinking there would be multiple values for average velocity but now i understand. Thankyou so much.

[Dave B]

Happy to help. Just in case it comes up in the future, I thought it might be worth noting that you could also have done:

plot(t,repelem(Vavg, numel(t)),'r',"DisplayName","Avg Velocity");