Atourist drops a penny off the empire state building. the penny hits the ground 12 seconds later. what is the velocity of the penny when it hits the ground?

117.6 m/s downward

Explanation:

The penny is moving with uniform accelerated motion (free fall motion), so we can find its vertical velocity at time t with the following suvat equation:

v = u + at

where

v is the velocity at time t

u is the initial velocity

a is the acceleration

The penny starts at rest, so

u = 0

Also, the acceleration is the acceleration of gravity,

where we have chosen upward as positive direction, so the acceleration is negative, since it is downward.

Substituting t = 12 s, we find the velocity of the penny when it hits the ground:

downward, since the sign is negative.