Algebra 1 problem

Question

The height of a fireworks rocket can be approximated by h = −7t² + 28t, where h is the height in meters and t is the time in seconds. Find the time it takes the rocket to reach the ground after it has been launched.

Answer 1

Not enough information.

The time is needed.

After getting the answer with "t"; then a gravity formula is used for time of drop from "h".