I drop my key off the side of a cliff. At the 5 seconds marks, how fast are the key moving?

477.9264 metres (1568 feet)

Explanation:

Gravity is measured by the acceleration that it gives to freely falling objects. At Earth's surface the acceleration of gravity is about 9.8 metres (32 feet) per second per second. Thus, for every second an object is in free fall, its speed increases by about 9.8 metres per second.

9.8 metres x 5 seconds = 477.9264 metres (1568 feet)

(that's if you use Earths gravity to calculate the keys speed)

1 a

2 b

3 b

4 d

5 d

6 d

explanation: