physics question, need help?

Question

A certain freely falling object requires 1.45 s to travel the last 25.5 m before it hits the ground. From what height above the ground did it fall?

Answer 1

Let us use algebra to solve this problem. Assume that it takes a total t seconds to fall from the original height to the ground. Since 0.5*g*T^2 is always the distance it travels in the initial T seconds, we have:
25.5 = 0.5*g*[t^2 - (t - 1.45)^2]
= 4.9 (2.9t - 1.45^2)
Therefore t = 2.52 (seconds) and this object was falling from the initial height of:
0.5*g*t^2 = 31.1(m)