1. A blob of material in outer space moves at 3 m/s when it collides and sticks to a half-as-massive blob initially at rest. Compared with the initial kinetic energy of the 3-m/s blob, the kinetic energy of the coupled blobs is

		one-third.
		two-thirds.
		three-quarters.
		not enough information

2. When Phil Physiker swings a buzzer over his head in a circle he hears

		the same Doppler effect that his friends off to the side hear.
		a throbbing hum.
		a steady hum.

3. Identical waves superimposed in phase produce a wave of increased

		amplitude.
		frequency.
		wavelength.
		All of these
		None of these

4. A boat at anchor is rocked by waves whose crests are 40 m apart and with wave speed 10 m/s. These waves reach the boat once every

		30 s.
		0.25 s.
		400 s.
		4 s.

5. Two tuning forks produce sounds of wavelengths 3.4 m and 3.3 m. Assuming the speed of sound is 340 m/s, the beat frequency produced is

		3.0 Hz.
		2.0 Hz.
		4.0 Hz.
		0.1 Hz.
		1.0 Hz.

6. When sound travels faster higher in the air than it does closer to the ground, sound bends

		upward.
		downward.
		neither of these

7. Sound energy that is not reflected is

		transmitted.
		absorbed.
		either or Both of these