Respuesta :

The ball will be at height 19 feet first at 0.7 sec and then at 1.42 sec.

Explanation:

We need to find the time at which the ball will be at height 19 feet.

Equation:

h = 3 + 34t - 16t²

19 = 3 + 34t - 16t²

16 = -16t² + 34t

-16t² + 34t - 16 = 0

On solving the equation, we get

t1 = 0.7 s and t2 = 1.42s

Therefore, the ball will be at height 19 feet first at 0.7 sec and then at 1.42 sec.