function [curvature] = Ujk(j, k, coords)
%UNTITLED2 Summary of this function goes here
%   Detailed explanation goes here
    eta = .02;
    mu = .02;
    alpha = .02;
    r0 =.3;
    x1 = coords(k, 1);
    x2 = coords(j, 1);
    y1 = coords(k, 2);
    y2 = coords(j, 2);
    theta1 = coords(k, 3);
    theta2 = coords(j, 3);
    
    rlength = sqrt((x2-x1)^2 + (y2-y1)^2);
    thetar = atan((y2-y1)/(x2-x1)) - theta1 + pi;
    if (x2 - x1) < 0
        thetar = thetar + pi;
    end
    
    f = alpha*(1 - (r0/rlength)^2);
    curvature1 = eta*cos(thetar)*sin(thetar);
    curvature2 = f*(sin(thetar));
    curvature3 = mu*cos(theta1 - theta2 + pi/2);
    curvature = curvature3 - curvature1 - curvature2;
end