A ball falls vertically after being dropped. The ball falls a distance d metres in a time of t seconds. d is directly proportional to the square of t.
The ball falls 20 metres in a time of 2 seconds.
The time (in seconds) that the ball takes to fall 605 m is
11
Given distance s is directly proportional to square of time t.
That is:
s=k.t220=4kk=5So,s=5t2605=5t2
t = 11 seconds