Chapter 8.5, Problem 10AYU

To determine

The function that relates the displacement $d$ of the object from its rest position after $t$ seconds and $a=10,T=3$ seconds, where an object attached to a coiled spring is pulled down a distance $a$ from its rest position, and then released. Assuming that the motion is simple harmonic with period $T$ and the positive direction of the motion is up.