A roofing tile falls from rest off the roof of a building. An observer from across the street notices that it takes 0.35 s for the tile to pass between two windowsills that are 2.45 m apart. How far is the sill of the upper window from the roof of the building?

Answer 1

Let H be the distance of the sill (base)of the upper window from the roof. The tile passes it in time

T = sqrt (2H/g)

You also know that

T + 0.35 = sqrt [2(H + 2.45)/g]

Solve those two simulataneous equations for H. T is easily eliminated.

0.35 = sqrt[2(H + 2.45)/g] - sqrt(2H/g)

Now solve for H