Physics 101 - Homework 2

Instructions: Complete this form and click submit. The answers will be posted on the course home page after the due date and before the next exam. If you want to change any of your answers after you click submit, then go back and give your answers again and click submit. Recall that the homework is not part of your grade. However, everyone is expected to complete all homework sets. A few of these questions may appear on an exam or clicker quiz.

Your Name:	e.g. John Doe
Your Campus ID:	e.g. 12345678
Your SFA Email Address:	e.g. doejd@titan.sfasu.edu
Due Date	9/17/2007 5:00PM

1. _________ is the bending in the direction a wave travels due to the fact that the medium is not uniform. a. refraction b. diffraction c. reflection d. absorption	A B C D E
2. A vibrating tuning fork causes an identical fork to vibrate. This is called ___________. a. refraction b. resonance c. beats d. reverberation	A B C D E
3. A grandfather clock runs too slow. Which of the following could you do to correct this?   a. remove some mass from the bob   b. increase the amplitude   c. move the bob down   d. move the bob up	A B C D E
4. The lowest frequency that can be produced on a guitar string has a wavelength ________ as long as the string. a. twice b. half c. four times d. one fourth	A B C D E
5. A decibel is a measure of a sound’s a. frequency b. wavelength c. speed d.  loudness e.  all of these	A B C D E
6. A violin and a piano sound different because they play sounds of different ____________.    a. amplitude                        b. quality    c. frequency                       d. wavelength	A B C D E
7. The natural frequency of a whistle is 1020 Hz. If you observe its frequency to be 1010 Hz, you can conclude a. you and the source are moving     farther away from each other b. the source is moving c. you and the source are both                     moving d. the source and you are moving     closer together e.  more that 40 m/s	A B C D E
8. Two waves having the same amplitude and frequency interfere as a crest meets a trough. The result will be _____. a. constructive interference b. destructive interference c. resonance d. standing waves	A B C D E
9. If you observe the beat frequency between two speakers to be ten hertz and if you know one of the speakers is 250 hertz, what are the other possible frequencies for the second speaker? a. 240 and 260 hertz b. 230 and 270 hertz c. 250 and 240 hertz d. 200 and 300 hertz	A B C D E
10. The longitudinal waves produced on a slinky more closely represent which of the following waves? a. water waves b. light waves c. sound waves d. transverse waves on a guitar      string	A B C D E

1.  What is the source of all sounds?
2.  What is the relationship between frequency and pitch?
3.  What is the average range of a young person's hearing?  Express your answer in Hertz.  What happens to this range as we age?
4.  Does sound travel faster in warm air than in cold air?  Defend your answer.
5.  How does a radio wave differ from a sound wave?
6.  How can the pitch of a guitar string be increased?
7.  What are the three principal classes of musical instruments?
8.  Why does a laser disc not wear out like a conventional phonographic record?
9.  How much more intense is sound at 100 dB than sound at 50 dB?

Need more examples or assistance?  If you have a new text book then you may be able to access tutorials and online quizes at www.MasteringPhysics.com.  The Access Code for this site is normally included in the first few pages of the book. Also, SFA physics major Rusty Permenter is available in the AARC for physics help between 6 and 8pm on Mondays. See Dr. B for help during these office hours.