Homework 5 Phys150, Fall 2003
Due Wed., October 15, 2003
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.
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.
- 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.
- Question A, Ch. 7 of March
- 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.
- 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.
- Exercise 2, Ch. 7 of March.
- 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.
- Discussion Question III-4 of Lightman, p. 277.
- 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.)