Answer
Since the ball starts above the lake and then falls down to the bottom of the lake, the direction of the average velocity is down.
Work Step by Step
The ball falls $5.20~m$ to the surface of the water and then falls $38.1~m$ to the bottom of the lake. The ball falls a total distance of $43.30~m$
The ball falls for a total time of $4.80~s$
We can find the average velocity:
$v_{ave} = \frac{\Delta y}{\Delta t} = \frac{43.30~m}{4.80~s} = 9.0~m/s$
The magnitude of the average velocity is $~~9.0~m/s$
Since the ball starts above the lake and then falls down to the bottom of the lake, the direction of the average velocity is down.
