A mass on a spring undergoes simple harmonic motion with amplitude A. a) In a time equal to three periods, what is the magnitude of the displacement of the mass? b) In a time equal to three periods, what actual distance did it travel? In the first part, I was at first trying to use an equation but realized that wasn't necessary. If it completes three full periods, it ends up at the same position it started at. But I don't understand how to calculate the second part. I was trying to use the equation x(t)=Acos(wt) to find the distance traveled, but I don't know t, nor do I know if this is even the right method for solving this. How am I supposed to know the actual distance traveled?