point(s) possible The height, h, of a projectile thrown straight up from the top of a 512-foot hill t seconds after being thrown upward with initial velocity vo fu/sec is given by h = = 16t- + vet + 512. In this exercise, for a given value of vo, find the time(s) when the projectile will (a) be at a height of 640 ft above the ground and (b) crash on the ground. Round your answers to two decimal places. Here Vo = 128 (a) How long will it take the projectile to reach a height of 640 feet? seconds (Use a comma to separate answers as needed. Type an integer or decimal rounded to two decimal places as needed.) (b) How long after throwing the projectile will crash it on the ground? seconds (Type an integer or decimal rounded to two decimal places as needed.)