Answer:
Logarithmic decrement is equal to 0.182
Explanation:
given,
amplitude decay = 9 dB Â Â Â Â Â
number of cycles = 12 cycles    Â
mass of the system = 7 kg    Â
spring stiffness = 3000 N/m      Â
logarithmic decrement = ? Â Â Â Â Â Â Â Â Â
now, Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
logarithmic decreament = [tex]ln\ D^{\frac{1}{n}}[/tex]
                    = [tex]ln\ 9^{\frac{1}{12}}[/tex]
                    =ln (1.2)
                    = 0.182
Hence, Logarithmic decrement is equal to 0.182