## HOW CAN I PROGRAME THIS?

### Leon (view profile)

on 17 Nov 2012

Pick two points on a surface (x1,y1) and (x2,y2). From selected position first one moves with the speed (vecotr)v=(v1,v2) and the other one with the speed of (vector)u=(u1,u2).

If points are getting close figure out when and where they are in the moment when they are the closest. Also computer must tell, if they are moving away. Plot graph of distnace in time between the 2 vectors.

A starting point of the first one is (0.4,603)m and the starting point of the secon one is (23,-908)m. Speed of first is vector(v)=(-0.1,-0.98)m/s and the second: vector(u)=(-0.2,1.1)m/s.

John Petersen

### John Petersen (view profile)

on 20 Nov 2012

Do you need help with the equations or the code?

Jan Simon

### Jan Simon (view profile)

on 20 Nov 2012

Is the surface flat? If so, the problem is to find the minimum distance between to lines.

## Products

No products are associated with this question.

### Eoin (view profile)

on 20 Nov 2012

It depends on how fancy you need to be...

you could do something like

```    dt = 1;
R1 = [X1 Y1]; V = [V1 V2];
R2 = [X2 Y2]; U = [U1 U2];
oldD = 999;
while(true)
R1 = R1+V*dt
R2 = R2+U*dt
D = sqrt(sum(R1-R2).^2);
if (D>oldD)
break;   % This will make the loop stop when the distance between the points starts to increase
end
oldD = D;
end```

More fancy would be to use an ordinary differential equation solver like ode45.

Plotting is left for you ;)

#### Join the 15-year community celebration.

Play games and win prizes!

MATLAB and Simulink resources for Arduino, LEGO, and Raspberry Pi