A mass suspended from a spring is raised a distance of 5 cm above its resting position. The mass is released at time t=0and allowed to oscillate. After one third of asecond, it is observed that the mass returns to its highest position, which was 4.5 cm above its resting position. What is the rate of change of the position of the mass at t = 2.1 seconds? Round your answer to three decimal places.