S₁ and S₂ are identical sound sources of frequency 656 Hz. S₁ is at O. S₂ moves anticlockwise with speed 4√2 m s⁻¹ on a circular path about O. P and R are diametrically opposite and Q is midway on the arc as shown; a detector is at P. Speed of sound is 324 m s⁻¹.
Physics · Wave Motion
S₁ and S₂ are identical sound sources of frequency 656 Hz. S₁ is at O. S₂ moves anticlockwise with speed 4√2 m s⁻¹ on a circular path about O. P and R are diametrically opposite and Q is midway on the arc as shown; a detector is at P. Speed of sound is 324 m s⁻¹.
Sub-question 1
When only S₂ is emitting sound and it is Q, the frequency of sound measured by the detector in Hz is [blank].
Sub-question 2
Consider both sources emitting sound. When S₂ is at R and S₁ approaches the detector with a speed 4 m s⁻¹,the beat frequency measured by the detector is [blank]Hz.