1 - In a student laboratory exercise, the wavelength of a 52,300 Hz ultrasound wave is measured to be 0.652 cm. Find the air temperature (in K).

2 - A person stands directly in front of two speakers that are emitting the same pure tone. The person then moves to one side until no sound is heard. At that point, the person is 7.40 m from one of the speakers and 7.44 m from the other. What is the frequency (in Hz) of the tone being emitted? (Assume air temperature to be 20C.)

3 - A baseball fan sitting in the "cheap seats" is d = 161 m from home plate (see the figure below). How much time elapses between the instant the fan sees a batter hit the ball and the moment the fan hears the sound? (Assume the speed of sound is 344 m/s, and the vertical distance can be ignored.)