Cannot plot iterations.
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I'm trying to plot iterations but it doesn't seem to be working. The figure pops up but no points do. This is confusing because both variables i'm plotting have the same size. How to I plot the iterations of v(k-1) against x ?
x=20:30;%range of inital velocities plotted
figure;
hold on
for i=20:30 %to iterate through a few intial velocities.
v0=i;
v(1)=v0;
s(1)=0;
for k=2:length(t) %This loop uses eulers formula to calculate velocity and displacment
muk=0.7;
a=-muk*g;
dvdt=a; %acceleration
dsdt = v(k-1); %velocity = displacment over time
%approx value of v at current step given previous value
v(k) = v(k-1) + dvdt*dt;
%approx value of s at current step given previous value
s(k)=s(k-1)+dsdt*dt;
%Break loop when velocity starts to become negative
if v(k) < 0
break
end
end
%Value before the first negative velocity value (this is the time where
%the car has stopped).
v(k-1) %this iterates through initial velocities corresponding to the final positive velocity value in each case
%plotting
plot(x,v(k-1))
end
1 Comment
Sriram Tadavarty
on 17 Mar 2020
what are the values of t, dt, and g? what are you trying to plot? The command plot(x,v(k-1)) will plot only the last element of v.. Try plot(x(1:length(v)),v)
Accepted Answer
KSSV
on 17 Mar 2020
Edited: KSSV
on 17 Mar 2020
clear all ; clc;
t=20:30;%range of inital velocities plotted
dt = min(diff(t)) ;
g = 9.81 ;
figure;
hold on
for i=20:30 %to iterate through a few intial velocities.
v0=i;
v(1)=v0;
s(1)=0;
for k=2:length(t) %This loop uses eulers formula to calculate velocity and displacment
muk=0.7;
a=-muk*g;
dvdt=a; %acceleration
dsdt = v(k-1); %velocity = displacment over time
%approx value of v at current step given previous value
v(k) = v(k-1) + dvdt*dt;
%approx value of s at current step given previous value
s(k)=s(k-1)+dsdt*dt;
%Break loop when velocity starts to become negative
if v(k) < 0
break
end
end
%Value before the first negative velocity value (this is the time where
%the car has stopped).
v(k-1) %this iterates through initial velocities corresponding to the final positive velocity value in each case
%plotting
plot(t,v(k-1),'*')
end
7 Comments
KSSV
on 17 Mar 2020
It is because your v(k-1) is only a single number i.e scalar. Which you can only plot by using markers.
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