Scientists working on a new rocket conduct a test launch with an initial velocity of 300 m/sec from a height of 500 m. Its height, (h), in meters, after (t) seconds is given by the formula h = 500 + 300t-9.8t^2. After how many seconds will the rocket again reach a height of 500 m? 32.2 s 1.8 s 30.6 s 28.8 s