The paper presents instructive interdisciplinary applications of constrained mechanics calculus in economics on a level appropriate for the undergraduate physics education. The aim of the paper is: * The values of the parameters where chosen according to [11]: κ = 1, A = 1, s = 0.25, v = 0.6 and the initial conditions were set as Y (0) = 10,Ẏ (0) = 4.