A = Point(xAxis)
B = (2, 1)
AB = Vector(A, B)
a = 4 (slider from -5 to 5, step 0.1)
b = 4 (slider from -5 to 5, step 0.1)
k = 1 (slider from -5 to 5, step 0.1)
ABe2: AB * AB
FAB: k * a * b / ABe2
ABu = UnitVector(AB)
fBA: FAB * ABu