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(phys011)[2010](f)quiz~3224^_10045.pdf
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Name: ________________ ID: _________________
PHYS 011, Quiz 6
Estimated time: 1:30 C 1:55 pm Nov. 29, 2010
1. (4 points) An ambulance moving at 42 m/s sounds its siren whose frequency is 450 Hz. A car is moving in the same direction as the ambulance at 25 m/s. What frequency does a person in the car hear
(a)
as the ambulance approaches the car?

(b)
after the ambulance passes the car? Speed of sound: 343m/s.


2. (6 points) A string of mass m = 2.500 g and length L = 0.800 m is under tension . = 325.0 N, The amplitude of the standing wave is 4.0 mm, see the figure.
(a)
What is the wavelength . of the transverse waves producing the standing-wave pattern in the Figure, and what is the harmonic number n?

(b)
What is the frequency f of the transverse waves and of the oscillations of the moving string elements?

(c)
What is the maximum magnitude of the transverse velocity um (along the y direction) of the element oscillating at coordinate x = 0.18 m?

(d)
When the transverse velocity of an element reaches maximum, what is its y position?