 In this video, we provide the solution to question number 14 from the practice final exam for math 1060 In which case we're asked to model the simple harmonic motion where the amplitude is 13 centimeters The period is three seconds and we're told that the displacement at time equals zero is zero So this last statement right here is telling us that if you start at zero You should be modeling this with a sine function if you actually had started at the maximum or minimum You'd be using a cosine with a plus or minus in front there So since so since we're starting off at zero here our model is gonna be y equals a times sine of 2 pi t over b right here Where a is going to be the amplitude so we end up with 13 times sine of 2 pi T over our period here, which has given us three seconds notice here that the coefficient in Inside here is supposed to be 2 pi over the period Like so and so since the period is three we plug that in there And so we end up with the correct model being 13 sine of 2 pi over 3 t Which we see is then choice D