Question

7)A train sounds its horn as it approaches an intersection. The horn can just be heard at a level of 60 dB by an observer 10 km away.

(a) What is the average power generated by the horn?
Answer must be in W

(b) What intensity level of the horn's sound is observed by someone waiting at an intersection 54 m from the train? Treat the horn as a point source and neglect any absorption of sound by the air.
Answer must be in dB

2) A 0.520-kg object attached to a spring with a force constant of 8.00 N/m vibrates in simple harmonic motion with an amplitude of 10.2 cm. (Assume the position of the object is at the origin at

t = 0.)

(a) Calculate the maximum value of its speed.
  cm/s

(b) Calculate the maximum value of its acceleration.
  cm/s²

(c) Calculate the value of its speed when the object is 8.20 cm from the equilibrium position.
cm/s

(d) Calculate the value of its acceleration when the object is 8.20 cm from the equilibrium position.
Answer must be in cm/s²

Answer 1

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