Answer:
d = 5t^2
Step-by-step explanation:
"d is directly proportional to the square of t"
d = kt^2
To find k use
"The ball falls 20 metres in a time of 2 seconds."
20 = k(2^2)
20 = k(4)
Divide both sides by 4
5 = k
Using k = 5 the formula becomes
d = 5t^2
