1. What is the frequency, in hertz that corresponds to each of the following periods?

(a)  0.10 s

(b) 5 s

(c)  I /60 s

2. What is the period, in seconds, that corresponds to each of the following frequencies?

(a) 10 Hz

(b) 0.2 Hz

(c) 60 Hz

3. A skipper on a boat notices wave crests passing his anchor chain every 5 s. He estimates the distance between wave crests to be 15 m. He also correctly estimates the speed of the waves. Show that this speed is 3 nus.

4. A weight suspended from a spring is seen to bob up and down over a distance of 20 cm twice each second. What is its frequency? Its period? Its amplitude?

5. A mosquito flaps its wings 600 vibrations per second, which produces the annoying 600-Hz buzz. Given that the speed of sound is 340 m/s, how far does the sound travel between wing beats? In other words, find the wave­length of the mosquito's sound.

6. On a keyboard, you strike middle C, whose frequency is 256 Hz.

(a) What is the period of one vibration of this tone?

(b) As the sound leaves the instrument at a speed of 340 m/s. What is its wavelength in air?

7. As shown in the drawing, the half-angle of the shock wave cone generated by a supersonic airplane is 45°. What is the speed of the plane relative to the speed of sound?

8. An astronaut on the Moon attaches a small brass ball to a 1.00-m length of string and makes a simple pendulum. She times 15 complete swings in a time of 75 seconds. From this measurement she calculates the acceleration due to gravity on the Moon. What is her result?