A tuning fork is struck, and the tips of the prongs (tines) are initially displaced 0.4 mm from their natural position at rest. The prongs oscillate at 440 Hz under damped harmonic motion. The sound is no longer audible once the displacement is less than 0.1 mm. What is the damping factor if the sound is no longer audible after 4.0 sec? Round to 2 decimal places.

A tuning fork is struck, and the tips of the prongs (tines) are initially displaced 0.4 mm from their natural position at rest. The prongs oscillate at 440 Hz under damped harmonic motion. The sound is no longer audible once the displacement is less than 0.1 mm. What is the damping factor if the sound is no longer audible after 4.0 sec? Round to 2 decimal places.