Chapter 14.1, Problem 1BE

A mass is oscillating on a frictionless surface at the end of a horizontal spring. Where, if anywhere, is the acceleration of the mass zero (see Fig. 14–2)? (a) At x = −A; (b) at x = 0; (c) at x = +A; (d) at both x = −A and x = +A; (e) nowhere.