APPLICATIONS

Question

The distance that a free falling object falls is directly proportional to the square of the time it falls (before it hits the ground). If an object fell 91 ft in 6 seconds, how far will it have fallen by the end of 9 seconds

Answer 1

Let d = distance (in feet) and t = time (in seconds)

 

Since d varies directly as t², d = kt², for some constant, k

 

Find k: 91 = k(6)²  k = 91/36 

 

So, d = (91/36)t²

 

When t = 9, d = (91/36)(9)² = 204.75 feet