Question

A stone is dropped from the 25th storey of a multistoried building and it reaches the ground in 5 s. In the first second, it
passes through how many storeys of the building (9 = m. 10ms-2)
A 1
B 2
C 3
none of these​

Answer 1

Explanation:

Let the height of each storey =h

2nd equation of motion from starting point to A-

h1 = 0 + ½ g (1)²

h1 = g/2

2nd equation of motion from starting point to B-

25h = 0 + ½ × g × (25)

25h = 25g/2

h = g/2

h = h1

Therefore,

Answer : 1 (A)

Hope it helps