Arthur drops a ball from a height of 81 feet above the ground. Its height, h, is given by the equation h = - 16t2 + 81, where t is the time in seconds. For which interval of time is the height of the ball less than 17 feet?

a. t>2

b. 0

c. t=2

d. - 2

We are given the free-falling equation in which the initial height above the ground is 85 feet. The equation is expressed h = - 16t2 + 81. When h is equal to 17 ft, then 17 = - 16t2 + 81; 0 = - 16t2 + 64, t is equal to 2 seconds. Answer then to this problem is C.