Welcome to *homework assignments* for the General
Physics I course, PHY 317K.
The homeworks on this page are for the section taught by
Professor
Vadim Kaplunovsky in Fall of 1999 (unique #56135).
Other sections assign different homeworks.

Most homework problems are taken from the Halliday, Resnick & Walker textbook; such problems are listed by problem numbers. All other problems are written in full as plain (html) text.

Please note that the physical laws and the formulae you use and the way you put them together are more important for your grade than the numbers you calculate. If you (correctly) derive the correct formula for the answer of a problem, you will receive partial credit even if your arithmetic is faulty. On the other hand, a numerical answer without a clear explanation of where it came from would earn you little credit even if it happens to be correct.

- Due:
- September 7.
- Textbook problems:
- Problems 6, 7, 11, 15, 16*, 19, 20, 33 and 36 at the end of
*Chapter 1*. - Non-textbook problem:
- An astronomical unit (AU) is the average distance of the Earth
from the Sun, approximately 1.5*10^8 km.

(a) The speed of light in vacuum is approximately 3*10^8 m/s; express this speed in in terms of AU/min (astronomical units per minute).

(b) A light year (ly) is the distance light travel (through the vacuum) in one year. How many astronomical units are there in one light year?

(c) A parsec (pc) is the distance at which 1 AU would subtend exactly an angle of exactly one second of arc (ie., 1/3600 of a degree), see figure 1-8 after problem 16 of the textbook (page 9). How many light years is one parsec?

(d) Express 1 ly and 1 pc in kilometers and in miles.

Note that although light-years are commonly used in popular literature to describe astronomical distances, the real astronomers prefer to measure interstellar distances in parsecs. - *Note:
- The non-textbook problem above was supposed to replace the textbook problem 16 -- they largely duplicate each other -- but somehow both got assigned. To correct this mistake, the two problems will be graded as one.

Solutions anavailable. Sorry.

- Due:
- September 14.
- Textbook problems:
- Problems 2, 5, 9, 14, 17, 19, 20, 27, 30, 31, 33, 37, 45, 50, 56,
58, 60, 61, 70, 71, 74 and 79 at the end of
*Chapter 2*. - Non-textbook problems:
- None

Solutions anavailable. Sorry.

- Due:
- September 21.
- Textbook problems:
- Problems 2, 6, 11, 14, 16, 17, 28 and 30 at the end of
*Chapter 3*. - Non-textbook problems:
- None
- Note:
- Please write your formulae before you calculate numbers. Draw pictures whenever appropriate.

Solutions available (after due date) in several formats: PDF, PostScript, TeX source, DVI.

- Due:
- September 28.
- Textbook problems:
- Problems 17, 18, 25, 30a, 34, 42, 43, 55, 74, 76, 79, 83 and 85
at the end of
*Chapter 4*. - Non-textbook problems:
- None

Solutions available (after due date) in several formats: PDF, PostScript, TeX source, DVI.

- Due:
- October 7. (Extended from October 5.)
- Textbook problems:
- Problems 58 and 63 at the end of
*Chapter 4*;*questions*2 and 8 and problems 10, 18, 22, 35, 38, 40, 52, 54, 58 and 68 at the end of*Chapter 5*. - Non-textbook problems:
- None

Solutions available (after due date) in several formats: PDF, PostScript, TeX source, DVI.

- Due:
- October 12.
- Textbook problems:
- Problems 6, 14, 20, 24, 60, 62, 66 at the end of
*Chapter 6*. - Non-textbook problem:
- Titan -- the largest moon of Saturn -- has a fairly dense atmosphere;
near Titan's surface, the `air' density is about 5.5 kg/m
^{3}. The*Cassini*mission to Saturn (to arrive on July 1, 2004) carries the*Huygens*probe which will enter Titan's atmosphere, aerobrake to a (relative) stop and then descend down to the surface on a parachute. Actually, several parachutes are used in a sequence; the final descent uses a drogue 'chute of diameter 3.03 m. The mass of*Huygens*-- or rather its Descent Module -- is 220 kg; the surface gravity of Titan is 1.35 m/s^{2}. Assume the drag coefficient of the drogue 'chute to be C=0.8 (I am not sure of the actual value but C=0.8 is typical) and plenty of time for the Descent Module to reach is terminal speed. What is the landing speed of the*Huygens*'s Descent Module?

Solutions available (after due date) in several formats: PDF, PostScript, TeX source, DVI.

- Due:
- October 26.
- Textbook problems:
- Problems 4, 8, 16, 26, 27, 33, 34, 42, 48 and 50
at the end of
*Chapter 7*. - Non-textbook problems:
- None

Solutions available (after due date) in several formats: PDF, PostScript, TeX source, DVI. Solutions re-posted on 11/1 to correct numerical errors in problems 26 and 42; and reposted again on 11/9 to correct yet another error in problem 26.

- Due:
- November 2.
- Textbook problems:
- Problems 38 and 40 at the end of
*Chapter 7*;*question*6 and problems 8, 16, 22, 32, 36, 40 and 60 at the end of*Chapter 8*. - Non-textbook problem:
- A 10~kg crate slides down a 5~m high frictionless ramp,
then continues sliding along a horizontal floor with a kinetic friction
coefficient µ
_{k}=0.5 until the friction force brings it to a stop. Use energy/work consideration to determine the final position of the crate.

Solutions available (after due date) in several formats: PDF, PostScript, TeX source, DVI.

- Due:
- November 9.
- Textbook problems:
- Question 6 and problems 4, 5, 8, 10, 20, 21, 28, 37, 42 and 46
at the end of
*Chapter 9*. - Non-textbook problems:
- None

Solutions available (after due date) in several formats: PDF, PostScript, TeX source, DVI.

- Due:
- November 18 (extended from November 16).
- Textbook problems:
- Problems 60 and 64 at the end of
*Chapter 11*;*question*2 and problems 16, 18, 25 and 31 at the end of*Chapter 13*. - Non-textbook problems:
- None
- Note:
- The next homework will be due Tuesday, November 23.

Solutions available (after due date) in several formats: PDF, PostScript, TeX source, DVI.

- Due:
- November 29 (Monday!) before 5 PM (Extended from November 23).
- Collection point:
- Professor Kaplunovsky's
*mail box*in room RLM 5.208 - Textbook problems:
*Questions*2 and 6 and problems 18, 21, 28, 29, 30, 34, 35, 37, 44 and 45 at the end of*Chapter 15*.- Non-textbook problems:
- None
- Note:
- The next homework will be due Thursday, December 2.

Solutions will be available after due time in several formats: PDF, PostScript, TeX source, DVI.

- Due:
- December 2.
- Textbook problems:
- Problems 53, 57, 66, 72 and 76
at the end of
*Chapter 15*. - Non-textbook problems:
- None

Solutions will be available after due time in several formats: PDF, PostScript, TeX source, DVI.

Last Modified: November 23, 1999 Vadim Kaplunovsky

vadim@physics.utexas.edu