Question

a) Explain the terms ‘crests’ and ‘trough’ of a wave? What type of waves consist of crests and troughs? 

b) The flash of a gun is seen by a man 3 seconds before the sound is heard. Calculate the distance of the gun from the man.

Answer 1

a) The crest is a part of a transverse wave which is the elevation experienced by the wave from the line which is above zero disturbance. Trough is also a part of a transverse wave which is the depression experience by the wave from the line which is below zero disturbance. 

b) Speed of sound = 332 m/s 

Time = 3s 

Speed = distance/time 

Distance = (Speed) (time) 

= 996 m