Question

time = 2 seconds represents 2 seconds since the stopwatch began. how would we represent 2 seconds before we started our stopwatch, when the rocket was still underwater?

Explanation:

Step1: Define time reference

The start - time of stopwatch is taken as the zero - point.

Step2: Represent negative time

Time before start is negative. So 2 seconds before start is represented as $- 2$ seconds.

Answer:

$-2$ seconds