Problem 1: A guitar string has a length of 65 cm and a mass of 5.8 grams. Calculate the speed of the transverse wave on the string if the tension is 60 N. Determine the fundamental frequency produced by the string.

Problem 2: A sound wave with a frequency of 500 Hz is traveling through air. The wave encounters a wall with a distance of 17 meters from the source. If the speed of sound in air is approximately 343 m/s, calculate the time it takes for the echo to return to the source. Problem 3) An orchestra conductor observes that the sound of the trumpet section is not as loud as the other instruments. The trumpet players are positioned at the back of the stage. Explain the acoustic phenomenon responsible for this observation and suggest a solution to improve their sound projection.