Isabella is playing with her yo-yo. The vertical distance Y (in cm) between the yo-yo and her hand t seconds after she first spins it out is modeled by the following function. Here, t is in radians. Y(t) = 40 cos ( 2π/3 t) – 71 How long does it take the yo-yo to fall all the way down from its peak, and then rise up to a vertical distance of -80 cm?