Two cars are moving on two perpendicular roads towards a crossing with uniform s

Sail E0 Webinar

Question

Two cars are moving on two perpendicular roads towards a crossing with uniform speeds of 72 km/h and 36 km/h. If second car blows horn of frequency 280 Hz, then the frequency of horn heard by the driver of first car when the line joining the cars makes angle of

45^{\circ}

with the roads, will be (velocity of sound is 330 m/s)

Options:

A . 321 Hz

B . 298 Hz

C . 289 Hz

D . 280 Hz

Answer: Option B
:
B
The component of velocity of source along line joining the car is

v_{s} = v_{1} c o s 45^{\circ} = 36 \times \frac{1}{\sqrt{2}} k m / h

= 5 \sqrt{2} m / s

Component of velocity of observer(second car) along the line joining the car is

Two Cars Are Moving On Two Perpendicular Roads Towards A Cro...

V_{0} = v_{2} c o s 45^{\circ} = 72 \times \frac{1}{\sqrt{2}} k m / h

= 10 \sqrt{2} m / s

n^{'} = \frac{v + v_{0}}{v - v_{s}} n = \frac{330 + 10 \sqrt{2}}{330 - 5 \sqrt{2}} \times 280

= \frac{344}{323} \times 280 H z = 298 H z

Was this answer helpful ?

Next Question

Submit Solution

More Questions on This Topic :

Question 1. A car emitting sound of frequency 500 Hz speeds towards a fixed wall at 4 m/s. An observer in the car hears both th....two sounds, the velocity of sound in air will be

Question 2. A whistle emitting a sound of frequency 440 Hz is tied to a string of 1.5 m length and rotated with an angular velocity....distance from the whistle will be (v = 330 m/s)

Question 3. A man standing on a platform hears the sound of frequency 605 Hz coming from 550 Hz train whistle moving towards th....sound is 330 m/s. What is the speed of train?

Question 4. A source of sound S is moving with a velocity 50 m/s towards a stationary observer. He measures the frequency of th....The velocity of the sound in the medium is 350 m/s.

Question 5. A band playing music at frequency f is moving towards a wall at a speed vb. A motorist is following the band with a spe....the expression for the beat frequency heard by the motorist is

Question 6. Speed of sound wave is v. If a reflector moves towards a stationary source emitting waves of frequency f with speed....with speed u, the wavelength of reflected waves will be

Question 7. The sound from a very high burst of fireworks takes 5 s to arrive at the observer. The burst occurs 1662 m above th....20∘C. Then (assume velocity of sound at 0∘C is 330 m/s)

Question 8. The frequency changes by 10% as the source approaches a stationary observer with constant speed Vs. What should be ....Vs ≪ v(v is the speed of sound in air).

Question 9. For a sound wave travelling towards +x direction, sinusoidal longitudinal displacement ξ at a certain time is given as....of air is B=5×105N/m2, the variation of pressure excess will be

Question 10. In the figure shown, a source of sound of frequency 510 Hz moves with constant velocity = 20 m/s in the direction s....equal to (speed of sound relative to air is 330 m/s)

Chapter 1 - GLOBAL STEEL SCENARIO & INDIAN STEEL INDUSTRY Part 1 : (13-04-2024) INDUSTRY AND COMPANY AWARENESS (ICA)

Direction Sense Test Part 1 Reasoning (Hindi)

Chapter 1 - RMHP / OHP / OB & BP Part 1 : (14-02-2024) GPOE

Cube & Cuboid Part 1 Reasoning (Hindi)

Data Interpretation (DI) Basic Concept Reasoning (Hindi)

Counting Figures Part 1 Counting Of Straight Lines Reasoning (Hindi)

Sail E0 free webinar Webinars

Real Numbers Part 7 Class 10 Maths

Real Numbers Part 1 Class 10 Maths

Polynomials Part 1 Class 10 Maths

Pie Chart - Test Paper 1 Data Interpretation Reasoning & DI

Tabulation - Test Paper 2 Data Interpretation Reasoning & DI

Test Paper 1 Direction Sense Test Reasoning & DI

ICA , RDIC,GFM Free Modal Test Paper - Non - Technical Branch Old Syllabus 2022 - SAIL Junior Officer E0

GFM Combined 1 Free Revision Test SAIL JO E-0