Question

How long would it take for a penny to fall from the top of the Empire State Building? The building is 381 meters.

Answer 1

Without air resistance, the distance an object falls is

                     D  =  (1/2) (gravity) (time)²

                 381 m  =  (1/2) (9.8 m/s²) (time)²

                 (time)²  =  (381 m) (4.9 m/s²)

                             =  (381/4.9)  seconds²

                   Time  =  √(381/4.9 sec²)

                           =        8.8 seconds   (rounded)