A boy standing some distance from the foot of a tall cliff claps his hands and hears an echo 0.5s later. If the speed of sound is 340ms‾¹, how far is he from the cliff?

A. 680m
B. 170m
C. 34m
D. 85m

Correct Answer:

Option D = 85m

Explanation

V = ^2d/_t
v = 340ms−1
t = 0.5s
d= ?

d = ^2d/₂=340×0.52 = 85m