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PhysicsSound WaveDopler's effectMedium2 minPYQ_2020

PhysicsMediumsingle choice

A motorcycle starts from rest and accelerates along a straight path at $2 m s^{- 2}$ . At the starting point, there was a siren which produced sound at a constant frequency. How far has the motorcycle gone from the starting point, If now the rider hears the frequency of the siren at $94 %$ of its value as compared to when the motorcycle was rest? (Speed = $330 m s^{- 1}$ )

Options:

Answer:

Solution:

For Motorcycle, $u = 0$ , $a = 2 m s^{- 2}$

Observe is in motion and source is at rest

$⟹ n^{'} = n \frac{v - v_{2}}{v + v_{s}}$

$⟹ \frac{94}{100} n = n \frac{330 - v_{o}}{330}$

$⟹ 330 - v_{o} = \frac{330 \times 94}{100}$

$⟹ v_{o} = 330 - \frac{94 \times 33}{10} = \frac{33 \times 6}{10} m s^{- 1}$

$s = \frac{v^{2} - u^{2}}{2 a} = \frac{9 \times 33 \times 33}{100}$

$= \frac{9 \times 1089}{100} = 98 m .$

Stream:JEESubject:PhysicsTopic:Sound WaveSubtopic:Dopler's effect

⏱ 2mℹ️ Source: PYQ_2020

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