A mass suspended on a spring will exhibit sinusoidal (sine wave) motion when it moves. If the mass on a spring is

9 cm off the ground at its highest position and 1 cm off the ground at its lowest position and takes 4 seconds to go
from the top to the bottom and back again, determine an equation to model the data.

impatient much?

Once is enough, thank you.
Repeated postings will not get faster or better responses.