Question

A stone dropped from the top of a cliff of height 44.1 m splashes into water in a pond near the base of
the cliff, after 3.126 s. Find the velocity of sound in air?
Ans: 350 m/s
​

Answer 1

Height of Tower = 78.4 m

Initial velocity of stone = 0

a = 9.8m/s^2 (given in question)

speed of sound in air approx. 340 m/s

s = ut_1+1/2gt_1^2

By putting all values in above equation,

t_1 = √156.8/9.8 = √16

t_1 = 4 s

Time taken to reach at top position,

t_2 = 78.4/340 = 0.230 s

t = t_1+t_2

  = 4+0.230 = 4.23 s

Answer 2

Answer:350ms^-1

Explanation:

Soln

You hear the sound of water splash after 3.126s.SO,the given time interval is from stone leaving your hand to disturbance in ear so lets solve this qstn in 2 parts .

Time taken by stone to reach the surface of pond ,

h = ut + (1/2)at^2

h = 0 + (1/2)9.8*t^2

(44.1*2)/9.8 = t^2

9 = t^2

t = 3s.

Moving onto second part ,

time taken by sound to reach your ear ,

t = 3.126-3

 =0.126

so,

h = ((u+v)/2)*t  (speed of sound is property of medium so always constant so v is replaced by u or vice versa)

     or

h = ut + (1/2)gt^2

solving for u or v , you will get 350ms^-1