Question 4: Consider an open-end air column that has a length of 50.0 cm, at a temperature of 25C, determine the frequency needed to produce fundamental resonance. I1:2, A:2) Question 5: A guitar string has a length of 65.0 cm. If the tension in the string is 250 N and the linear density is 1.30 g/cm. determine the frequency is needed to produce the fourth harmonic on the string. (1.2, A:2) Question 6: A stationary observer hears the siren of an ambulance at a frequency of 950 Hz while the siren on the ambulance operates at a frequency of 850 Hz. Is the ambulance driving towards the observer or away from the observer? What is its speed? Speed of sound is 342 m/s (K:1, I:1, A:2) Question 7: Assume the siren on the fire truck has operates at a frequency of 600 Hz and the fire truck travels at a speed of 95 km/hr [E] towards a stationary observer. If the wind speed is 40 m/s [W], at a temperature of 21C, what is the siren heard by the observer? Would this value be higher or lower than the situation without wind? (K:1, I:2, A:1) Question 1: Describe constructive and destructive interference and provide a sketch that demonstrates both. (K:2, C:2) Question 2: Consider the two waves traveling at a speed of 1.0 m/s shown below, sketch the wave form after 3.0 seconds. Each grid is 1 m. (A:2, C:2) Y e PP T T e P r Question 3: Short answer questions A. An upright wave travels to the right encounters an obstacle then it reflects as an inverted wave and a lower amplitude. What did it encounter? Explain. (C:2) B. An inverted wave travels to the right encounters an obstacle then it reflects back as an inverted wave with the same amplitude. What did it encounter? Explain (C:2) C. Which of the wave terms describes the frequency and which describes the loudness? (K:2)