A cycle wheel of mass $$M$$ and radius $$R$$ fitted with a siren at a point on its circumference is mounted with its plane vertical on a horizontal axle at about $$3\ \text{ft}$$ above the ground. An observer stands in the vertical plane of the wheel at $$100\ \text{m}$$ away from the axle on a horizontal platform. The siren emits a sound of frequency $$1000\ \text{Hz}$$ and the wheel rotates clockwise with a uniform angular speed $$\omega=\pi\ \text{rad}/\text{s}$$. Initially at $$t=0\ \text{s}$$ the siren is nearest to the observer and moves downwards. The observer records the highest pitch of sound for the first time after, taking the speed of sound in air as $$330\ \text{m}/\text{s}$$.