The collective behavior of many interacting examples of these systems is described in the Kuramoto model. The expression “mu times the quantity 1 minus x-squared” multiplies x-dot in an ODE describing one of these systems. Long build-ups followed by sudden discharges are characteristic of the “relaxation” type of these systems. Cartwright and Littlewood studied a nonlinear one of these systems named for Dutch engineer Balthasar van der Pol. The time evolution of one type of these systems traces an ellipse in phase space. The dissipation of one type of these systems is described by their Q-factor. An LC circuit behaves as one of these systems, (10[2])as it satisfies the generic differential equation, “mx-double-dot equals minus kx.” (10[1])For 10 points, Hooke’s law describes the “simple harmonic” type of what systems? ■END■