Question

A stone is dropped from a height 7.6m . Splash of sound is heard after 3.91sec velocity of sound is (m/s)

Answer 1

Solution :-

Provided :-

• H = 7.6 m

• Time after which sound is heard = 3.91 sec

Now time of fall

→ -h = ut - 1/2 gt²

→ - 7.6 = 0(t) - 1/2 (9.8) t²

→ 7.6 = 4.9t²

→ t = √(1.551)

→ t = 1.245 sec

Now time of fall + time of sound to travel 7.6 m = 3.91 sec

→ Time to travel 7.6 m by sound = 3.91 - 1.245

= 2.67 sec

Now as v = d/t

→ v = 7.6/2.67

→ v = 2.85 m/s

But this answe isn't possible as we know that the range of velocity of sound varies from 340m/s to 360m/s

So please re-consider the numerical values.