Hi, I searched thread similar to my problem but none of the responses helped me to calculate the right answer. I am given the speed (v=400 m/s), wavelength (.16 m) and amplitude (1.4 mm). I need to calculate time for particle of the string to move through a total distance of 1 km. I calculated the period and also how many wavelengths were necessary to get to 1 km and then multiplied (as did the others who had problems with this). I don't understand what to do.