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A motor cycle starts from rest and accelerates along a straight path at `2m//s^(2)`. At the starting point of the motor cycle there is a stationary electric siren. How far has the motor cycle gone when the driver hears the frequency of the siren at `94%` of its value when the motor cycle was at rest ? (Speed of sound = `330ms^(-2))`A. 49 mB. 98 mC. 147 mD. 196 m |
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Answer» Correct Answer - B when source in stationary and observer is moving away from the source . ` n^(t) =n((V-V_(0))/(V))` `implies 0.94 n=n((330-V_(0))/(330))` ` implies V_(0) =19.8 m//s` `therefore V_(0)=0+2as` ` therefore S=(V_(0)^(2))/(2a)` `=(19.8xx19.8)/(2xx2)` =98 m. |
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