Direct and Inverse Proportions

Question

The distance, s m, through which a heavy object falls from rest is directly proportional to the square of the time, t seconds, taken.

The object takes 3 seconds to fall 45 m.

Find

a. the distance the object will fall from rest in 7 seconds.

b. the time taken by the object to fall 20 m

Answer 1

h(t) = 5t^2

h(3) = 45

a. h(7) = 5(7^2) = 5(49) = 245 meters in 7 seconds

b h(t) = 20 =5t^2

t^2 =4

t = sqr4 =2 seconds to fall 20 meters