A stone is thrown straight up from the edge of a roof, 675 feet above the ground, at a speed of 16 feet per second.
A. Remembering that the acceleration due to gravity is -32 feet per second squared, how high is the stone 2 seconds later?
B. At what time does the stone hit the ground?
C. What is the velocity of the stone when it hits the ground?

You can earn partial credit on this problem.