# 1. A planet moves in an elliptical orbit around a star. This is a two-body system. Which of the following must stay constant during the orbit?

1.

A planet moves in an elliptical orbit around a star. This is a two-body system. Which of the following must stay constant during the orbit?

a. Kinetic energy of the planet

b. The angular momentum of the planet

c. The potential energy of the system

d. The force on the planet

e. Two of the above answers are correct

2.

Two sound waves have identical wavelength and frequency. Which of the following must also be the same for the two waves?

a. Their speed

b. Their amplitude

c. Their period

d. Two of the above answers are correct

3.

Rank the speed of the following wave pulses on a violin string with the following characteristics:

I. Length L, Mass M, and Tension F

II. Length L, Mass 2M, and Tension 2F

III. Length L, Mass M and Tension 2F

IV. Length L/2, Mass M/2, Tension 4F

a. I<II<III<IV

b. I<II<III=IV

c. I=II<III<IV

d. I=II=III<IV

4.

Two sound waves have the same frequency and wavelength, but wave 1 has twice the amplitude of wave 2. Which of the following must be true?

a. They are moving at different speeds

b. The have the same energy per wavelength

c. They have different media in which the travel

d. The energy per wavelength of each is different

e. None of the above is true

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