A MET office employee, who is standing still, observes a stormcoming towards him at 15 m/s. The thunder that he hears (the‘observed’ frequency) is at a frequency of 140 Hz. The speed ofsound is 343 m/s. i) Show that the frequency the employee hearswill increase if he decides to move toward the storm at 4 m/s. ii)The employee hears a frequency of 157 Hz as he drives away from thestorm. At what speed is he driving away? iii) There is a delaybetween the discharge of lightning in the middle of the storm andthe arrival of the sound of thunder. Using physics principles,explain this delay and how one might use this information toestimate distance from the observer to the storm.
