Question

3) A body dropped from the top of the tower covers a distance 7x in the last second of its journey where x is the distance covered in first second . How much time does it take to reach the ground ?

Answer 1

we know that distance travelled in nth second is given as

s_n = (1/2).a.(2n-1)

here a = g

and for n = 1

s_n = x = g/2

and also given

s_n = 7x

or

(1/2).g.(2n-1) = 7.(g/2)

or

(2n-1) = 7

thus, total time taken to fall

n = 8/2 = 4 secs