A train is traveling at 30.0 m/sm/s relative to the ground in still air. The frequency of the note emitted by the train whistle
is 262 HzHz. The speed of sound in air should be taken as 344 m/sm/s. Part A What frequency fapproachfapproachf_approach is heard by a passenger on a train moving at a speed of 18.0 m/sm/s relative to the ground in a direction opposite to the first train and approaching it
The problem is based on Doppler's effect , for which expression is as follows
n is apparent frequency , n₀ is original frequency , V is velocity of light , v₀ is velocity of observer and v_s is velocity of source , both coming towards each other.
Via the equation of potential energy PE = mgh where m is mass, g is the average gravity on earth and h is the height. In this case m = 400 kg, g = 9.8, h = 10 m thus:
