Question

66. A stone is dropped from the top of a tower
and it hits the ground at t = 3.5 s. If the veloc-
ity of sound in air is 300 m s1, find the time
taken to hear the sound by a person on the top of
the tower, from the instant the body is dropped.
(g = 10 m s-2)​

Answer 1

Stone

initial velocity = 0 m/s

time taken = 3.5 sec

gravitational acceleration = 10 m/s

so

distance

s = ut + (at^2) ÷ 2

s = 61.25 meter

Now

Sound

initial velocity = 300 m/s

distance to travel = 61.25 meter

time taken = distance ÷ velocity of sound

= 61.25 ÷ 300

= 0.204 sec