To solve this problem we will apply the concepts related to the Period such as the relationship between the time taken to make the oscillations, the frequency as the inverse of the period, the amplitude as the midpoint of the distance traveled and the linear velocity as the product between the velocity angular and amplitude, this is
PART A) The period would be defined by the time it takes to perform the 15 oscillations so the unit value would be
PART B) The frequency as the inverse of the period
PART C) The amplitude as the midpoint of the distance traveled
PART D) The linear velocity is the product between the amplitude and the angular frequency, then
Where
Therefore the linear velocity is