a body dropped from the top of a tower falls through 40 m during the last two seconds of its fall.

Let the h is the  height of cliff and stone takes n seconds to reach the ground.

The distance travelled by the particle in nth sec

S_nth = u + a ( 2n - 1) / 2

Here, S_nth = 40 m , u = 0 , a = 10 m/s²

so,    40 = 10 ( 2n - 1) / 2

or,           n = 4.5 sec

So, the stone takes 4.5 s to reach the ground from top of the tower.

Now, the height of the tower

h = ut + gt² /2

    = 0 + 10 (4.5 )² /2

    = 101.25 m