Two trains move in the same direction on two close tracks. The train A sounds a horn of single frequency of 1 kHz . At a certain instant of time, when both trains move at the same speed of 36 ~km / hr , the two straight tracks deviate at an angle of 60^ with each other. Velocity of sound in air is 300 ~m / s . Which of the following statement(s) is/are true?

Step-by-step solution

At the bend, when the second train B passes the bend and moves at 60^ to the first train A . The apparent frequency heard by the passenger on train B , is given by n_a= [ V-u_B V+u_A 60^ ] n Given V=300 ~m / s , u_A=u_B=36 ~km / h =10 ~m / s . Thus n_a= [ 300-10 300+5 ] 1 kHz = ( 290 305 )(1000)=950.82 ~Hz The passenger on train A is in the same train as source and so will always hear the source frequency of 1 kHz . If the train A turns on the bend on the second track while the passenger on train B hears the sound