The shot has a constant downward acceleration of . Since acceleration is constant, the velocity of the ball is given by
where is the shot's vertical velocity at time and is its initial vertical velocity. We're given that . So
gives the shot's velocity at time .
Because acceleration is constant, we also know that
where is the average vertical velocity, is the vertical displacement at time , and is the initial displacement at . We're given an initial displacement of , so the displacement of the shot is
The shotputter is 1.90 m tall, a difference of 0.20 m from the initial height of the throw. So we want to find the time for the ball to reach a displacment of -0.20 m: