A cheerleader waves her porn-porn in SHM with an amplitude of 18.0 cm and a frequency of 0.850 Hz. Find
(a) The maximum magnitude of the acceleration and of the velocity;
(b) The acceleration and speed when the porn-porn's coordinate is x = +9.0 cm;
(c) The time required to move from the equilibrium position directly to a point 12.0 cm away.
(d) Which of the quantities asked for in parts (a), (b), and (c) can be found using the energy approach used in Section 13.3, and which cannot? Explain.