An observer standing on a railway crossing receives frequency of   2 . 2   kHz and 1 . 8   kHz when the train approaches and recedes from the observer. Find the velocity (in m   s - 1 ) of the train. (The speed of the so

Question

An observer standing on a railway crossing receives frequency of &#160; 2 . 2 &#160; kHz and 1 . 8 &#160; kHz when the train approaches and recedes from the observer. Find the velocity (in m &#160; s - 1 ) of the train. (The speed of the sound in air is 300 m s - 1 .)

Quantrex Academy · Accepted Answer

Correct answer: 30

f 1 = f 0 ( V ± V 0 ) ( V ∓ V S ) = f 0 v V ∓ V S W h e n a p p r o a c h e s : 2.2 × 10 3 = f 0 300 300 - V s ...(i) W h e n r e c e d e s : 1.8 × 10 3 = f 0 300 300 + V s ...(ii) Dividing (i) by (ii) 2 . 2 1 . 8 = 3 0 0 + V S 3 0 0 - V S ⇒ 4 0 . 4 = 6 0 0 2 V S ⇒ V S = 30 m s - 1

An observer standing on a railway crossing receives frequency of   2 . 2   kHz and 1 . 8   kHz when the train approaches and recedes from the observer. Find the velocity (in m   s - 1 ) of the train. (The speed of the sound in air is 300 m s - 1 .)

Correct answer

Step-by-step solution

More from Waves and Sound

An observer standing on a railway crossing receives frequency of &#160; 2 . 2 &#160; kHz and 1 . 8 &#160; kHz when the train approaches and recedes from the observer. Find the velocity (in m &#160; s - 1 ) of the train. (The speed of the sound in air is 300 m s - 1 .)

Correct answer

Step-by-step solution

More from Waves and Sound

An observer standing on a railway crossing receives frequency of 2 . 2 kHz and 1 . 8 kHz when the train approaches and recedes from the observer. Find the velocity (in m s - 1 ) of the train. (The speed of the sound in air is 300 m s - 1 .)