Question

Your fishing bobber oscillates up and down from the current in the river in a harmonic motion. The bobber moves a total of 2.5 inches from its high point to its low point then returns up to the high point every 3 seconds. Write an equation modeling the motion of the bobber at its high point at time t = 0.

Answer 1

a max at t=0 indicates a cosine wave

you have the period and displacement, and there is no phase shift

just follow the standard format