A ball is thrown into the air with an upward velocity of 80 feet per second. The function h = -16t2 + 80t models the height h, in feet, of the ball at time t, in seconds. When will the ball reach the ground?

The ball reaches the ground when its height is 0. Set the model equal to zero: -16t² + 80t = 0, which factors as -16t(t - 5) = 0. The solutions are t = 0, when the ball was thrown, and t = 5, when it returns to the ground. So the correct choice is after 5 seconds.

AI-written and checked against the verified answer.