Question
#17 help asap please, Thank you
C)2247Hz ti used a end , D) 90 Hz E) 93.6 Hz , one ? The ,peed of sood in air 330 avs? S. A vertical spring with a spring constant 38 N/m is hunging from a ceiling, A smal object with a mass 23 kp then attached. The object is then pulled down and released. The speed of the object when it is 10 cm from th equilibruim position is 1.9 m/s. How far down was the object pulled? A) 24.472 cm B) 47.8 cm C) 72.2 cm D) 23.104 cm E) 46 cm 16. An increase of 30 dB increases the sound intensity by a facsor ofd A) 1000 B) 2 100 C) 120 D) 840 E) 100. fo 17. A person in a parked car sounds the horm. The frequency of the horn's sound is 460 Hz. A driver in an approeching car nesu t frequency or the born's sound as 505 What is the speed orthe approaching car, ( Use 30 ns forthe speed oCiud A) 69.69 m's B) 31.7 m's C) 25.3 m's D) 33.35 m's E) 23.276 m's 8. A very loud train whistle has an acoustic power outpat of 90 warts. If the sound energy speeats out spherically, whet in the nes level in dB at a distance of 115 metes from the traint (le-10n Was/m) A) 108 dB B) 51.84 dB(C)/8734 dB D) 19458 dB E) 864 dB A mass on a spring vibrates in simple harmonic motion at a frequency of 6 Hi and an amplimds of 7 cm. It timer ia tanal v displacement is a maximum (ence x 7 cm when-O), what is the displacement of the mass when t-2.4 s? 4/-5.663cm B)-17.5 cm C) 12.6 cm D) 4cm E) 432 cmv.A-Co(yit S0 ealgn) 34 gm cube of ice, initially at 0°C is dropped into 220 gm of water in a 110 gm aluminam comanet,oh witls heat for aluminum is 0.215 calign-e and
Explanation / Answer
17)
Applying doppler's effect:
f = (V + Vr)(f0) / (V + Vs )
where V = speed of sound = 343 m/s
Vr = velocity of reciever = v
Vs = velocity of source = 0
505 = (343 + v)(460) / (343 + 0)
343 + v = 376.5
v = 33.5 m/s
Ans: Option D is Correct
