PLEASE HELP ME WITH THIS PHYSICS ASSIGNMENT THERES A TIME LIMIT

Question 12 Doppler Waves Not yet When a wave source is in motion, the wavelengths in front of and behind the source are altered. answered Marked out of Time left 2:28:13 1.00 (This diagram is not to scale.) Flag question Wave fronts Wave source Direction of motion 7-2 Refer to the diagram Doppler Waves to answer this question. The diagram shows the wave fronts created by a sound source moving to the right. The waves that precede the source have a wavelength (1) of 1.40 m, while those that trail the source have a wavelength (2 ) of 1.80 m. If the speed of sound in air is 326 m/s, what is the true frequency of the source? Select one: O a. 233 Hz O b. 204 Hz O c. 197 Hz O d. 181 HzQuestion 13 When the source of a sound wave is moving toward an observer, which of the following will appear to occur? Not yet answered Select one: Marked out of 1.00 a. The apparent wavelength of the sound is greater than the true wavelength of the sound. Flag O b. The apparent wavelength of the sound is less than the true wavelength of the sound. question c. The apparent speed of the wave is greater than the true speed of the wave. O d. The apparent speed of the wave is less than the true speed of the wave.Question 14 A spring is stretched to a length of 5.40 m. You generate a standing wave using a frequency of 4.75 Hz. If there are 5 antinodes along the spring, Not yet answered then the speed of the wave in the spring is m/s. (Record your three-digit answer in the answer box.) Marked out of 1.00 Flag questionQuestion 15 Which of the following conditions are required for two waves to create a standing wave in a spring? Not yet answered I. The waves must be travelling in opposite directions. Il. The waves must have equal amplitudes. Marked out of 1.00 Ill. The waves must have equal wavelengths. Flag Select one: question O a. I, ll, and Ill O b. I and ll only O c. ll and Ill only O d. I and Ill onlyQuestion 16 For a mechanical wave, the medium can be defined as Not yet answered Select one: Marked out of 1.00 O a. the material in which the wave travels. Flag O b. the average amplitude of the wave. question O c. the average distance between two crests. O d. the average distance between a crest and a trough.Question 17 A wave in a spring, stretched to a length of 3.60 m, travels at a speed of 2.80 m/s. What is the lowest resonant frequency for this spring? Not yet answered Select one: Marked out of 1.00 O a. 0.389 Hz Flag O b. 0.572 Hz question O c. 0.778 Hz O d. 1.02 Hz