For the system shown , the block has a mass of 1.5 kg and the spring constant k=8.0 N/m . suppose that the block is pulled down a distance of 12 cm and released .if the friction force is given by - bv, where b=0.23 kg /s , find the number of oscillations made by the block during the time interval required for the amplitude to fall to one-third of its initial value.