1. [-/1 Points] WAUNIPHYSAV1 16.P.041.TUTORIAL. ASK YOUR TEACHER PRACTICE ANOTHER Two speakers, s1 and 52, are located 0.550 m apart as shown in the gure below. Sally stands 0.750 m away from speaker 51, indicated by the "X" on the gure. The speakers are connected to an adjustable oscillator and always emit the same sound in phase at the same frequency. (Use 343 m/s for the speed of sound in your calculations.) (a) If Sally cannot hear anything at her location due to destructive interference of sound from the two speakers, what is the lowest possible frequency of sound the speakers emit? Hz (b) The frequency is now changed to 1901 Hz. Sally stands at the same point. Her friend Mark moves speaker 52 (along the same axis) to the closest point to speaker 51, but not coinciding with 51, such that Sally hears a maximum of sound intensity. What is the new distance between 51 and 52? m 2. [-11 Points] WAUNIPHYSAV1 16.P.043. ASK YOUR TEACHER PRACTICE ANOTHER What beat frequencies result if a piano hammer hits three strings that emit frequencies of 987.8, 164.8, and 196.0 Hz? (Enter your answers from smallest to largest.) smallest Hz HZ largest Hz 3. [I1 Points] WAUNIPHYSAV1 16.P.040. ASK YOUR TEACHER PRACTICE ANOTHER Two speakers are located 0.22 m apart, with the rst speaker 0.76 m directly away from Sally as shown in the gure. (a) Determine the lowest frequency that will result in destructive interference at Sally's location (indicated by X in the gure) if the two speakers are in phase. Use 343 m/s for the speed of sound. :1 Hz 2 (b) Given that the phase difference is related to the path difference by the equation q) = (7\")(AX), determine the lowest frequency that will result in destructive interference at Sally's location if the two speakers have a phase difference of It. :Hz 4. [I1 Points] WAUNIPHYSAV1 16.P.044. ASK YOUR TEACHER PRACTICE ANOTHER You and a friend frequently play a trombone duet in a jazz band. During such performances it is critical that the two instruments be perfectly tuned. Since you take better care of your trombone, you decide to use your instrument as the standard. When you produce a tone that is known to be 200 Hz and your friend attempts to play the same note, you hear 5 beats every 3.00 seconds. Your ear is good enough to detect that your trombone is at a higher frequency. Determine the frequency of your friend's trombone. (Enter your answer to at least 1 decimal place.) :Hz 5. [-/1 Points] WAUNIPHYSAV1 16.P.046.TUTORIAL. ASK YOUR TEACHER PRACTICE ANOTHER A diagnostic ultrasound echo is reected from moving blood and returns with a frequency 322 Hz higher than its original 2.00 MHz. What is the velocity of the blood? (Enter the magnitude of the velocity. Use 1540 m/s as the speed of sound through human tissue.) m/s @ Tutorial 6. [-/1 Points] WAUNIPHYSAV1 16.P.047. ASK YOUR TEACHER PRACTICE ANOTHER (a) What frequency is received by a person watching an oncoming ambulance moving at 105 km/h and emitting a steady 873 HZ sound from its siren? The speed of sound on this day is 345 m/s. Hz (b) What frequency does she receive after the ambulance has passed? Hz 7. [I1 Points] WAUNIPHYSAV1 16.P.055. ASK YOUR TEACHER PRACTICE ANOTHER Two trains approach each other on separate but adjacent tracks. Train 1 is traveling at a speed of 34.0 m/s and train 2 at a speed of 26.2 m/s. If the engineer of train 1 sounds his horn which has a frequency of 520 Hz, determine the frequency of the sound heard by the engineer of train 2. (Use 343 m/s as the speed of sound. Enter your answer to the nearest H2.) H2 8. [I1 Points] WAUNIPHYSAV1 16.P.049. ASKYOUR TEACHER PRACTICE ANOTHER A light-rail commuter train blows its 200 Hz horn as it approaches a crossing. The speed of sound is 339 m/s. (a) An observer waiting at the crossing receives a frequency of 216 HZ. What is the speed of the train? m/s (b) What frequency does the observer receive as the train moves away? Hz