Answer:
Check below
Step-by-step explanation:
With the information given, let's consider some aspects of Sandy Beach behavior.
1. Sandy Beach
Let's calculate the period of this function



The Period of sin function is 
2. Verifying the Range, in this case the lapse of time.
A <em>sin</em> function varies from -1 to 1, i.e.
![-1\leq sin(s) \leq1 \therefore-4\leq 4sin(s)\leq4 \\ adding \:the\:5\\-4+5\leq 4sin(s)\leq4+5\\\\\1\leq4sin+5\leq9 \therefore t=[1,9]\\](https://tex.z-dn.net/?f=-1%5Cleq%20sin%28s%29%20%5Cleq1%20%5Ctherefore-4%5Cleq%204sin%28s%29%5Cleq4%20%5C%5C%20adding%20%5C%3Athe%5C%3A5%5C%5C-4%2B5%5Cleq%204sin%28s%29%5Cleq4%2B5%5C%5C%5C%5C%5C1%5Cleq4sin%2B5%5Cleq9%20%5Ctherefore%20t%3D%5B1%2C9%5D%5C%5C)
So, within an interval form 1 to 9 hours the waves at Sandy Beach come and go.
3. Check the graph below.