Question

an object is dropped from the top of a tower distance it covers in last second is 7 times the distance it covered in the first second find time of flight?

Answer 1

we know that distance travelled in nth second is given as

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

here a = g

and for n = 1

sn = x = g/2

and also given

sn = 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