A mass-spring system has displacement x(t) = 0.03 sin(5t + π/6) meters. When the displacement is zero, what is true about the velocity and acceleration?

Which of the following conclusions is best supported by the evidence that for the weak acid equilibrium $$HA \rightleftharpoons H^+ + A^-$$, the reaction quotient $$Q = \frac{[H^+][A^-]}{[HA]}$$ calculated from the given concentrations (yielding $$Q = 1.0 \times 10^{-3}$$) is greater than the acid dissociation constant $$K_a = 1.8 \times 10^{-5}$$?