According to Newton’s second law, the acceleration of a particle is proportional to the net force acting on it. In cases, in which the net force depends on the actual position and on the actual velocity of the particle, the system is described by a second-order ODE (due to the velocity and the acceleration being the first and the second derivatives of the position, respectively). In cases, in which the net force depends on both the actual and some delayed values of the particle’s position and velocity, the system is described by a second-order DDE. Second-order systems are therefore often used in engineering to model dynamic behavior. In this chapter, some special second-order scalar DDEs are considered and analyzed by the semidiscretization method.