Starting from where? And can I assume that the velocity is upwards? On the surface of the Earth, you need to solve this equation for “t”.
0 = V0 * t + 0.5 g t^2
Where: V0 = +7.3 m/s, g = -9.80665 (this varies a tiny bit around the world).
So we get t = 0 and t = -2 V0 / g. That works out to approximately 1.49 seconds, without considering air resistance.