Question

A motor cycle 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 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^–1).

(a) 49m 

(b) 98m

(c) 147m 

(d) 196m.

Answer 1

(b) : The source is at rest, the observer is moving away from the source.