The vertical position of a ball suspended by a rubber band is given by the equation

y(t) = (3.4 m)sin(0.49 t/s − 0.40) − (0.4 m/s)t + 5.4 m.

(a) What are the equations for velocity and acceleration for this ball? (Use the following as necessary: t.)

(b) For what times between 0 and 30 s is the acceleration zero? (Enter your answers as a comma-separated list.)