Kenny klutz drops his physics book off his aunt's high-rise balcony. it hits the ground below 1.5 s later?
a. with what speed does it hit?
b. how high is the balcony ? ignore air drag.

Gravity causes a falling object to fall 9.8 m/s faster every second it falls.

Kenny's book started out with no speed when it was dropped. 
1.5 sec later, it was falling at (9.8 x 1.5) = 14.7 m/s .

During the fall, its average speed was  1/2(0 + 14.7) = 7.35 m/s .

Distance it covered = (average speed) x (time) =

                                             (7.35 m/s) x (1.5 sec) = 11.025 m