A motorcycle starts from rest and accelerates along a straight path at 2m/s² . At the starting point of the motor cycle , there is a stationary Electric siren . How far has the motor cycle hone when the driver hears the frequency of the siren at 94% of its value when the motor cycle was at rest ? (speed of sound = 330m/s) [AIEEE 2009]
Answers
Answered by
0
Answer:
98 m
Explanation:
Let x=distance
From Doppler's effect0.49f=(
330
330−2
x
)⇒x=98m
Answered by
4
Explanation:- For motor cycle u= 0 , a= 2m/s²
observer is in motion and source is at rest , then apparent frequency ,
- ⟹n' = n(v-v₀)/v+vₛ
- ⟹ 94/100n= n(330-v₀)/330
- ⟹ 330-v₀ = 330×94/100
- ⟹ v₀ = 330- 94×33/10
- = 33×6/10m/s
- s = v² -u²/2a= (33×6/10)²/2a
- S= 9×1089/100
- = 9× 1088/100 ≈ 98mAnswer
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