(a) why are sound waves called mechanical waves ? list two practical applications of reflection of these waves. (b) a stone is dropped from the top of a tower 125 m high into a pond of water at the base of the tower. when is the splash heard at the top ? (g = 10 m/s2 and speed of sound = 340 m/s)

Amass attached to a spring is displaced from its equilibrium position by 5cm and released. the system then oscillates in simple harmonic motion with a period of 1s. if that same mass–spring system is displaced from equilibrium by 10cm instead, what will its period be in this case? a mass attached to a spring is displaced from its equilibrium position by and released. the system then oscillates in simple harmonic motion with a period of . if that same mass–spring system is displaced from equilibrium by instead, what will its period be in this case? a) 0.5sb) 2sc) 1sd) 1.4s