2d projecti basic; It is not letting me plot x,y,t and the input was working now it only takes inital velocity

function [x,y,v]=projectile(vO,angle,time)
 
   vO=input('enter initial velocity greater than 0')
 
   angle=input('enter angle')
   time=input('enter time ')
   vOy= vO*sind(angle);
    vOx= vO*cosd(angle);
   ay= -9.81;
   x=vOx*time; 
   y=vOy*time+0.5*ay*(time^2);
   vx=vOx;
   vy=sqrt(vx^2+2*ay*y);
   v=sqrt(vx^2+vy^2);
    if vO==0
       msg='error initial velocity must be greater than 0'
       error(msg)
    else
    end
   x0=0;
y0=0;
k=0;
 
v=vO;
g=9.81;
t=0:0.1:time;
x=x0+v*cosd(angle)*t;
y=y0+v*sind(angle)*t-(g*t.^2)/2;
figure
hold on
plot(x,y)
xlabel('time[s]')
ylabel('position[m]')
title('postion vs time')
hold off

Answer 1

[Amrtanshu Raj]

Hi,

I have updated the code and it is working now.

You should also note that you are plotting y vs x and not position vs time. I have added all the plots as subplot. Also you can refine the code.

function [x,y,v]=projectile()

    vO=input('enter initial velocity greater than 0 :');
    angle=input('enter angle :');
    time=input('enter time :');
    
    if vO==0
        msg='error initial velocity must be greater than 0';
        error(msg)        
    end
    
    vOy= vO*sind(angle);
    vOx= vO*cosd(angle);
    
    ay= -9.81;
    
    x=vOx*time;
    y=vOy*time+0.5*ay*(time^2);
    
    vx=vOx;
    vy=sqrt(vx^2+2*ay*y);
    v=sqrt(vx^2+vy^2);
    

    x0=0;
    y0=0;
    k=0;

    v=vO;
    g=9.81;
    t=0:0.1:time;
    x=x0+v*cosd(angle)*t;
    y=y0+v*sind(angle)*t-(g*t.^2)/2;
    subplot(3,1,1)
    plot(x,y)
    xlabel('Position_x[m]')
    ylabel('Position_y[m]')
    title('postion')
    
    subplot(3,1,2)
    plot(x,t)
    xlabel('Time[s]')
    ylabel('Position_x[m]')
    title('Position_x vs Time')
    
    subplot(3,1,3)
    plot(x,y)
    xlabel('Time[s]')
    ylabel('Position_y[m]')
    title('Position_y vs Time')
    

Hope this helps !!