On Earth, the acceleration of gravity is 9.8 m/s² downward.
This means that any falling object gains 9.8 m/s of speed downward
for every second it falls.
Since the penny fell for 1.5 seconds, its downward speed at the
end of that time is (1.5 x 9.8) = 14.7 m/s faster than at the beginning
of that time.
Since it was dropped gently from somebody's hand ... and not THROWN
down ... its speed at the beginning is zero. So its speed after 1.5 seconds
is 14.7 m/s, and its velocity after 1.5 seconds is 14.7 m/s downward.
