For this case we have an equation of the form: h (t) = - (1/2) * a * t ^ 2 + vo * t + h0 Where, vo: initial speed a: acceleration: h0: initial height. We have the following equation: h (t) = - 16t2 + 19t + 110 Therefore, the initial velocity is: vo = 19 feet / s Answer: The initial velocity when the rock is thrown: vo = 19 feet / s