MATLAB: Modeling speed and height of a toy rocket using while loops

MATLABpracticewhile loop

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Best Answer

A little more like this perhaps:
g = 9.81 ;
m = 0.05 ; 
f = 16 ; 
%find velocity and height of the rocket in the first 15s
%this loop starts when time in seconds is 0 and repeats the commands until
%15 secods 
t1 = 0; dt = 0.01;
t = 0; v = 0; h = 0;  % to store values for plotting
i = 1; % counter
while t1<0.15
    a = f/m - g;
    v1 = a*t1; 
    h1 = .5*a*t1^2; 
    t1 = t1 +dt; 
    i = i+1;
    t(i) = t1; v(i) = v1; h(i) = h1;
    
end 
%this while loop models the velocity and height after 15 seconds until the
%parachute opens 
v2 = v1;
t2 = t1;
while v2 > -20
    h2 = h1 + v1*(t2-t1)-.5*g*((t2-t1)^2);
    v2 = v1 - g*(t2-t1); 
    t2 = t2 + dt;
    i = i+1;
    t(i) = t2; v(i) = v2; h(i) = h2;
end
%this while loop models the velocity and height from when the parachut
%opens till the rocket hits the ground. 
h3 = h2; 
t3 = t2;
v3 = v2;
while h3>0 
    h3 = h2 + v3*(t3-t2);
    t3 = t3+dt;
    i = i+1;
    t(i) = t3; v(i) = v3; h(i) = h3;
end 
subplot(2,1,1)
plot(t, h),grid
xlabel('t'),ylabel('h')
subplot(2,1,2)
plot(t, v),grid
xlabel('t'),ylabel('v')
Note that the question specifies the powered flight for 0.15s not 15s.
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