Homework 5 Phys150, Fall 2003
Due Wed., October 15, 2003

1. Decsribe in your own words the difference bewteen a "particle" and a "wave". This is a fundamental difference in classical physics and is also a difference in practice in our everyday experience. Give at least three distinct ways in which particles and waves behave very differently.

2. In this problem you are asked to compare gravtitational force to electric force for a specific example. The forces can be worked out in a way similar to the "worked examples" of chapter 4 and 6 of March.
A. Calculate the electric force in Newtons between two objects with charge 0.002 C spaced a distance 0.5 m apart.
B. Calculate the gravtitational force in Newtons between the same two objects if each has mass 1000 Kg.
3. Question A, Ch. 7 of March
4. Question C, Ch. 7 of March. Include in your answer a statement of how you can change the frequency by one octave by changing your finger position.
5. Question D, Ch. 7 of March. See also exercise 4, which is essentially the same and clarifies what you should show be on your sketch.
6. Exercise 2, Ch. 7 of March.
7. Calculate the wavelengths of the following three electromagnetic waves:
A. Waves from WILL-AM which broadcasts at a frequency of 580 Khz = 580,000/s.
B. Waves from WILL-FM which broadcasts at a frequency of 90.9 Mhz = 90.9 x 106/s.
C. Visible light from a laser pointer that has a frequency 7 x 1014/s.
8. Discussion Question III-4 of Lightman, p. 277.
9. Calculate the Lorentz factor gamma for two cases:
A. v = 1.5 x 108 m/s.
B. v = 1.5 x 106 m/s.
(Note that these are similar to Lightman's worked problems on p. 264 and to the worked exercise in March, Ch. 8.)
• Remember that there are hints, worked exercise that covers several examples, and there are answers to odd-numbered problems that are very similar to problems assigned.