Plotting two variables from a loop

Question

Yash Bakrania 2020-4-3

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/515122-plotting-two-variables-from-a-loop

评论： Yash Bakrania 2020-4-3

Hi, the code below indicates 2D equations of the projectile of a payload delivery system. The numerical process induces varying values for 'x' and 'y'. I am trying to plot the projectile motion of the object (so x vs. y) for every time step (loop). How can I do this?

% Constants
g=9.81;
m=1.5;
A=0.028; 
Cd=0.8;
rho=1.225;
B=(rho*Cd*A)/2;
Dt=1e-6;
% Initial values
x=0;
y=6.4008; %21 ft
V=12.5;
alpha=90;
Vx=V*sind(alpha);
Vy=V*cosd(alpha);
t=0;
for k=1:1e9
    
    if y<0
        break
    end
    
    ax= -(B/m)*(V*Vx);
    ay=(B/m)*(V*Vy)-g;
    x=x+Vx*Dt+0.5*ax*(Dt^2);
    y=y+Vy*Dt+0.5*ay*(Dt^2);
    Vx=Vx+ax*Dt;
    Vy=Vy+ay*Dt;
    V=sqrt((Vx^2)+(Vy^2));
    
    t=t+Dt;
end

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Answer 1

KSSV 2020-4-3

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/515122-plotting-two-variables-from-a-loop#answer_423809

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% Constants
g=9.81;
m=1.5;
A=0.028; 
Cd=0.8;
rho=1.225;
B=(rho*Cd*A)/2;
Dt=1e-6;
% Initial values
x=0;
y=6.4008; %21 ft
V=12.5;
alpha=90;
Vx=V*sind(alpha);
Vy=V*cosd(alpha);
t=0;
X = zeros([],1) ; 
Y = zeros([],1) ; 
for k=1:1e9
    
    if y<0
        break
    end
    
    ax= -(B/m)*(V*Vx);
    ay=(B/m)*(V*Vy)-g;
    x=x+Vx*Dt+0.5*ax*(Dt^2);
    y=y+Vy*Dt+0.5*ay*(Dt^2);
    Vx=Vx+ax*Dt;
    Vy=Vy+ay*Dt;
    V=sqrt((Vx^2)+(Vy^2));
    
    t=t+Dt;
    X(k) = x ;
    Y(k) = y ; 
end
plot(X,Y)