close all
clear all

P = [143.4 104.1 62.1  0.0]
native = [72.1 56.2 28.2 6.1];

lbs = P*0.25*pi*(5^2-.75^2);


[y] = polyfit(native,lbs,1);

x = 0:100;
Force = y(2)+x*y(1);

figure
plot(native,lbs,x,Force);