Guys what's this? one of my friend asked me to identify ​

The graph shows the distance y, in inches, a pendulum moves to the right (positive displacement) and to the left (negative displacement), for a given number of seconds x. how many seconds are required for the pendulum to move from its resting position and return? enter your answer in the box.

The parabola opens: y=√x-4 (principal square root) up down right left

How many kilometers are equal to 5 miles? use 1 mile ≈ 1.61 kilometers. !