Assume that a watermelon dropped from a tall building falls y=16t^2 in t sec. Find the watermelon's average speed during the first 3 sec of fall and the speed at the instant t=3sec.
a. 48 ft/sec; 96 ft/sec
b. 49 ft/sec; 98 ft/sec
c. 24 ft/sec; 48 ft/sec
d. 96 ft/sec; 49 ft/sec