Answer:
[tex]d = 2.75[cos \frac{\pi}{4}]t[/tex]
Step-by-step explanation:
Let's take the equation for the height of a buoy:
d = Acos(wt)
Where[tex] A = \frac{5.5}{2} = 2.75[/tex]
(We divided by 2 because there are 2 directions for the magnitude of total displacement, which is the amplitude of a periodic function)
[tex]w =\frac{2 \pi}{T}[/tex] where T = 8 seconds
[tex]w = \frac{2 \pi}{8} = \frac{\pi}{4}[/tex]
Lets substitute the values, in the equation, we have:
[tex]d = 2.75[cos \frac{\pi}{4}]t[/tex]
Therefore, the equation that describes the motion of the buoy if it is at its high point at time t = 0 is
[tex]d = 2.75[cos \frac{\pi}{4}]t[/tex]