Imagine a ringing bell set inside a sealed glass jar. Once all the air is removed and a vacuum is created, the ringing sound is no longer heard. Explain why this happens.   The glass prevents any sound from escaping.   The pressure of the outside air causes the sound to remain within the jar.   The lack of air in the jar causes the ringing to stop.   Without air, the sound waves cannot travel to the ear.

A loudspeaker on a pole at the same height as your ears is radiating 100 W of sound energy in all directions. You are walking directly toward the speaker at 0.60 m/s. Assume your ears are 20 m away from the loudspeaker itself and, although it is not realistic, ignore all reflections of sound from nearby objects such as the ground. What is the sound intensity level at the location of your ears? Express your answer with dB units. ► View Available Hint(s) B Submit Part B dß dt = Submit μÀ || Value What is the rate (dB/s) at which the sound intensity level is increasing? Hint: Use the chain rule and the relationship log₁0 x = ln x/ ln 10. Express your answer in decibels per second. ► View Available Hint(s) Units VE ΑΣΦ www ? ? dB/s

In each of the four scenarios shown in the images, a large bat lets out a short burst of ultrasonic sound, which a smaller bat hears a moment later. If the large bat flies at 2.320 m/s and the small bat flies at 13.80 m/s, order the frequencies that the smaller bat detects in the four scenarios from highest to lowest. Assume that the speed of sound is 343.0 m/s. Highest frequency A D B. A B C Lowest frequency Answer Bank In Scenario C, part of the large bat's signal reflects off the small bat and returns to the large bat, warning it of the smaller bat's presence. If the initial signal has a frequency of 66.70 kHz, what return frequency fr will the large bat detect? Calculate the final frequency to four significant figures. fr Incorrect kHz Ꭰ

Two students are standing the same distance from a source of sound. The first student receives a power of 68 × 10-6 W in their eardrum. The second student receives σ = 1.2 times more power in their eardrum. What is the ratio of the diameters of the students eardrums?  d1/d2= If the second students eardrums have a diameter of d=1cm what was the intensity of the sound that the student heard in watts per square meter?  I=