Create a quadratic equation for the given problem and then solve the equation with a related function using a graphing calculator. If necessary, round your answer to the nearest hundredth.

A ball is dropped from 15 feet above the ground. The function h(t) = −16t^2 + 15, where t represents the time in seconds, gives the height, in feet, of the ball above the ground. When will the ball be 6 feet above the ground?

The ball will be 6 feet above the ground after about
second(s).