1. [-/1 Points] WAUNIPHYSAV1 16.P.002. ASK YOUR TEACHER PRACTICE ANOTHER The wave function s(x, t) = (2.00 mm)cos [(15.0 m'1)X (865 s'l)t] represents the motion of a sound wave through air. Here, 5(X, t) is the displacement of a particular element of the medium at the location x and time t. (a) Find the shortest time after t = 0 at which the instantaneous displacement from the equilibrium is 0.410 mm at the location X = 0.0510 m. ms (b) For the time you determined in part (a), nd the rst location on the positive X axis at which the instantaneous displacement is zero. m 2. [-/1 Points] WAUNIPHYSAV1 16.P.004. ASK YOUR TEACHER PRACTICE ANOTHER You are setting up an experiment to study the relation between displacement and pressure amplitude of sound waves in air (density = 1.20 kg/m3). The maximum wavelength of a sound wave that you are able to generate is 4.65 m with an upper limit of 0.860 N/m2 for the pressure amplitude. What is the displacement amplitude of the sound wave you are able to generate? The speed of sound in air is 343 m/s. urn 3. [-/1 Points] WAUNIPHYSAV1 16.P.008. ASK YOUR TEACHER Dolphins make sounds in air and water. What is the ratio of the wavelength of the sound in air to its wavelength in water? Assume air temperature is 200C and the speed of sound in sea water at 20.0C is 1540 m/s. Asea water 4. [-/1 Points] WAUNIPHYSAV1 15.P.044. ASK YOUR TEACHER PRACTICE ANOTHER After your school's team wins the regional championship, students go to the dorm roof and start setting off fireworks rockets. The rockets explode high in the air and the sound travels out uniformly in all directions. If the sound intensity is 2.02 x 10'5 W/m2 at a distance of 173 m from the explosion, at what distance from the explosion is the sound intensity half this value? :m 5. [I1 Points] WAUNIPHYSAV1 16.P.030. ASK YOUR TEACHER PRACTICE ANOTHER A simplied version of our voice production system consists of considering the breathing passage and the mouth to be a tube closed at one end. (3) Determine the frequency of the fundamental (to the nearest Hertz) if the simulation tube is 0.227 m long and the air temperature is 35.0C. The speed of sound in air at 0C is 331 m/s. Hz (b) Assuming that the temperature dependence for helium is the same as for air, determine the frequency of the fundamental (to the nearest Hertz) if the air is replaced by helium. The speed of sound in helium at 0C is 965 m/s. Hz 6. [-/1 Points] WAUNIPHYSAV1 16.P.035. ASK YOUR TEACHER PRACTICE ANOTHER You have a length of tubing that is closed at one end. You cut the tubing into two pieces of unequal length, giving you a tube open at both ends and a tube closed at one end. You establish that the fundamental frequency for the new open tube is 233 Hz and for the new closed tube is 742 Hz. Determine the fundamental frequency for the original closed tube. (Use 343 m/s as the speed of sound.) Hz 7. [I1 Points] WAUNIPHYSAV1 16.P.037. ASK YOUR TEACHER PRACTICE ANOTHER A iron rod clamped at its center is set into longitudinal vibration. The length of the rod is 1.23 m and the speed of sound in the metal is 5130 m/s. (a) What is the fundamental frequency of vibration in this rod? :le (b) The standing waves formed in this rod can be compared to which of the following? 0 a tube closed at one end 0 a tube closed at both ends 0 a tube open at both ends 8. [I1 Points] WAUNIPHYSAV1 16.P.050. ASK YOUR TEACHER PRACTICE ANOTHER Two eagles y directly toward one another, the rst at 15.0 m/s and the second at 14.7 m/s. Both screech, the rst emitting a frequency of 3943 Hz and the other one of 3800 Hz. What frequencies do they receive if the speed of sound is 330 m/s? (Enter your answers to at least the nearest 10 Hz.) rst eagle Hz second eagle Hz 9. [-/1 Points] - WAUNIPHYSAV1 16.P.052. ASK YOUR TEACHER PRACTICE ANOTHER Two test pilots are in identical jets that produce a characteristic tone of 567 Hz. One jet is stationary on the airstrip and the second is approaching the airstrip at a speed of 76.6% the speed of sound. The pilot of each jet listens to the sound produced by the other jet. Determine the following. (a) which pilot hears a smaller Doppler shift? 0 the stationary pilot 0 the moving pilot (b) the frequency heard by the pilot in the moving jet HZ (c) the frequency heard by the pilot in the stationary jet HZ 10. [-/1 Points] WAUNIPHYSAV1 16.P.054. ASK YOUR TEACHER PRACTICE ANOTHER You are at a railroad crossing waiting for a freight train traveling at a speed of 35.8 m/s to pass by. The frequency of the train's horn is 325 Hz. (Use 343 m/s as the speed of sound.) (a) Determine the overall change in frequency you detect as the train moves from approaching to receding. Use the sign of your answer to indicate whether the frequency increases or decreases. Hz (b) Determine the overall change in wavelength you detect as the train moves from approaching to receding. Use the sign of your answer to indicate whether the wavelength increases or decreases. rn