Answer:
<em>The object takes 3.84 seconds to return to earth.</em>
Explanation:
<u>Projectile Motion</u>
It's when an object projected above the ground at a certain velocity, moves along a curved path under the action of gravity.
The initial velocity has two components, given by:


Where vox is the initial component of the velocity in the horizontal direction, voy is the initial component of the velocity in the vertical direction, and t is the time.
The object reaches a maximum height and then it returns to the ground. The time it takes to reach the maximum height can be calculated when the vertical component of the velocity is zero:


The initial vertical component of the velocity is 18.8 m/s, thus:

The total time is double that time:

The object takes 3.84 seconds to return to earth.