A 5.0-kg block is attached to a spring whose force constant is 125 N/m. The block is pulled from its equilibrium position at x = 0 m to a position at x = + 0.687 m and is released from rest. The block then executes damped oscillation along the x-axis. The damping force is proportional to the velocity. When the block first returns to x = 0 m, its x-component of velocity is -2.0 m/s and its x-component of acceleration is + 5.6 m/s
What is the damping coefficient b?