Short Answer: (5 points each) 1.) Explain why sound waves need a medium through which to travel. 2.) Draw a transverse wave. Indicate the following: direction of particle motion, crest, trough, wavelength, amplitude 3.) What are two reasons that the speed of sound is different at higher altitudes? Explain these differences. 4.) What is the sound barrier? How is it sound barrier was so difficult in 1947. produced? Explain, in terms of physics, why breaking the 5.) Explain the Doppler effect. ; (10 points each) 1.) Blue Whales are the loudest creatures: they can emit sound waves with an intensity of 3.0 x 103 W/m2. If this intensity is measured 4.0 m from its source, what power is associated . with the sound wave? 2%) You are rockin at a Lynyrd Skynyrd concert. You are 10.0 m away from the nearest speaker. . The speaker is putting out 1000 W. What is the relative intensity of this sound? ~ 4.) A sound is emitted in a valley. It takes two seconds for the sound to leave its source, bounce off Of the left wall, and then return to the source. It takes four seconds for the sound to leave its source, bounce off of the right wall, and then return to its source? The temperature in the valley is 30 C. How wide is the valley