Are added to D2L under “Sample and Past Exams and Solutions” — Nicholas Kuzma 2014/03/24 17:14
Please check your grades at D2L. The announcement there gives details about the final exam curve, letter-grade break-points and the student stats. — Nicholas Kuzma 2014/03/25 09:48
Dear Class,
The first term of my engagement as PSU faculty has almost come to a close - the final grades are due on Tuesday, and our grader is working away full steam trying to finish by Monday.
Here is a number of things I want you to take a look at by the end of the business day on Monday though:
Best of luck, and hopefully I'll see you in my Physics 203 class! Those who are excited about it and want to have an early start, please read chapters 13 and 14 in our textbook. I'll post the syllabus and get the new wiki going soon… Please google “Kuzma PDX” to go to my homepage and check whether there is a link to the new wiki. — Nicholas Kuzma 2014/03/22 17:29
survey_workshop_form.pdf - Deadline for extra credit: Tuesday March 18, 11:59pm PDT survey_workshop_form.doc - a Word document for those who cannot edit/save the PDF
Your attachments will be separated from your emails and processed anonymously by Ameena. Your answers will not affect your extra credit grade as long as you answered some questions and did not email a blank form.
Be sure to check the PDF before emailing it to see if it is blank. In google chrome's PDF plug-in for mac, it will sometimes just save a blank form. In order to preserve your data, you can alternatively follow this procedure:
Use WolframAlpha for calculations
notes12.pdf – please download before class!
Find the mass of a bucket (3 US gallons) of mercury. The density of Hg is $\rho_\text{Hg}=13.5\,$g/cm^{3}.
Steps:
You and your bike weigh 170 pounds. When you sit on it, each wheel makes an 8 cm^{2} imprint on the pavement. Find the pressure in the tires.
Steps:
A partially submerged cylindrical tank is pulled out of the lake with the closed end up and the open end still under water. The level of the water inside the tank is 2 m above the lake water level. Find the air pressure in the air bubble trapped in the tank. Can the water level in the tank be 15 m above the lake surface?
Steps:
A solid object made from a pure element weighs 4.413% less when submerged in pure water at room temperature (compared to its weight in air). What material is it made from?
Steps (as discovered by Archimedes):
An injection of 2 mL of vaccine takes 10 s. The syringe inner diameter is 5 mm, the needle is 5 cm long, with a 0.2$\,$mm inner diameter. Find the force required to perform the injection, assuming the viscosity of the vaccine is equal to that of water (0.001 N$\cdot$s/m^{2}). If the vaccine is squirted into the air straight up (to remove the air bubble), how high will it go? Assume the length of the syringe (not including the needle) can be calculated from the volume of the vaccine and the syringe cross-section.
Steps:
A river boat with a blunt bow, moving with a velocity $v=18.52\,\frac{\text{km}}{\text{hr}}$ (10 knots), “piles up” water at the bow. Find the height of the resulting wake at the bow. Steps:
From: Walker, James S. “Ch. 16 Temperature and Heat.” Physics. Custom ed. Vol. 2. Upper Saddle River, NJ: Pearson/Prentice Hall, 2004
Table 16-1 | Table 16-2 | Table 16-3 | |||
Coefficients of Thermal Expansion Near 20$\,^\circ$C | Specific Heats at Atmospheric Pressure | Thermal Conductivities | |||
---|---|---|---|---|---|
Substance | Coefficient of linear expansion $\alpha$ $\;\left[K^{-1}\right]$ | Substance | Specific Heat $c$ $\;\left[\frac{\text J}{{\text{kg}}\cdot{\text K}}\right]$ | Substance | Thermal Conductivity $k$ $\;\left[\frac{\text W}{{\text m}\cdot{\text K}}\right]$ |
Lead | $2.9\times 10^{-5}$ | Water | 4186 | Silver | 417 |
Aluminum | $2.4\times 10^{-5}$ | Ice | 2090 | Copper | 395 |
Brass | $1.9\times 10^{-5}$ | Steam | 2010 | Gold | 291 |
Copper | $1.7\times 10^{-5}$ | Beryllium | 1820 | Aluminum | 217 |
Iron (steel) | $1.2\times 10^{-5}$ | Air | 1004 | Steel (low carbon) | 67 |
Concrete | $1.2\times 10^{-5}$ | Aluminum | 900 | Lead | 34 |
Window glass | $1.1\times 10^{-5}$ | Glass | 837 | Stainless steel alloy 302 | 16 |
Pyrex glass | $3.3\times 10^{-6}$ | Silicon | 703 | Ice | 1.6 |
Quartz | $5.0\times 10^{-7}$ | Iron (steel) | 448 | Concrete | 1.3 |
Substance | Coefficient of volume expansion $\beta$ $\;\left[K^{-1}\right]$ | Copper | 387 | Glass | 0.84 |
Silver | 234 | Water | 0.60 | ||
Ether | $1.51\times 10^{-3}$ | Gold | 129 | Asbestos | 0.25 |
Carbon tetrachloride | $1.18\times 10^{-3}$ | Lead | 128 | Wood | 0.10 |
Alcohol | $1.01\times 10^{-3}$ | Wool | 0.040 | ||
Gasoline | $9.5\times 10^{-4}$ | Air | 0.0234 | ||
Olive oil | $6.8\times 10^{-4}$ | ||||
Water | $2.1\times 10^{-4}$ | ||||
Mercury | $1.8\times 10^{-4}$ |
notes13.pdf – please download before class!
Download PDF version here (not corrected yet, see below)
To determine the specific heat of an object, a student heats it to 100$\,^\circ$C in boiling water. She then places the 98.3 g object in a 193 g aluminum calorimeter containing 147 g of water. The aluminum and water are initially at a temperature of 20.0$\,^\circ$C, and are thermally insulated from their surroundings.
If the final temperature is 23.7$\,^\circ$C, what is the specific heat of the object?
Hint: Solve it by balancing the heat released from cooling of the object (100$\,^\circ$C $\rightarrow$ 23.7$\,^\circ$C) and the heat absorbed by the aluminum body + the water of the calorimeter (20.0$\,^\circ$C $\rightarrow$ 23.7$\,^\circ$C).
At what temperature Celsius and Fahrenheit scales are equal?
Steps:
Contracting window frame
A 6 x 6 ft window is encased in an aluminum frame. Find the minimal gap on each side at room temperature (20$\,^\circ$C) to avoid cracking at $-40\,$degrees.
Note that the temperature difference $\Delta T$ is the same in K units as in C$^\circ$ (difference) units.
Gasoline expansion
How much do you gain by filling up a 15 gal tank in the winter at 20$\,^\circ$F and using it in summer at 90$\,^\circ$F?
Calories from chocolate
How many steps up the stairs are necessary to burn off all the calories from 1/4 of the bar of chocolate pictured to the right? Assume the human muscle is 100% efficient in converting the calories to mechanical energy, each step is 15 cm high, and your mass is 70 kg.
Steps (literally and figuratively):
1 bar of “Green & Black's” = Mt. Hood |
---|
The cost of OHSU sky-tram going up is about the price of a bar of “Green & Black's” - not a bad deal! (Going down is free, by the way)
Losing weight in your sleep
A sleeping person “burns” about 70 W of energy just to keep warm during sleep. Assuming the thermostat in the bedroom is set to 72$\,^\circ$F and that the area of the upward-facing side of the body is 0.5 m^{2},
Steps:
How hot a black electric stove needs to be to radiate 1 kW. The diameter of the hot plate is 6 inches.
Steps:
These values depend somewhat on temperature and pressure. See properties of water for more details.
Property | Symbol | Value | Unit |
---|---|---|---|
Latent heat of water vaporization | $L_v({\text H}_2{\text O})$ | $22.6\times 10^5$ | $\frac{\text J}{\text{kg}}$ |
Specific heat of water | $c_\text{wat}$ | 4186 | $\frac{\text J}{{\text{kg}}\cdot{\text K}}$ |
Latent heat of ice fusion | $L_f({\text H}_2{\text O})$ | $33.5\times 10^4$ | $\frac{\text J}{\text{kg}}$ |
Specific heat of ice | $c_\text{ice}$ | 2090 | $\frac{\text J}{{\text{kg}}\cdot{\text K}}$ |
Value | Units |
---|---|
8.314 | m^{3} Pa K^{-1} mol^{-1} |
0.08206 | L atm mol^{-1} K^{-1} |
8.206 x 10^{-5} | m^{3} atm mol^{-1} K^{-1} |
62.364 | L torr mol^{-1} K^{-1} |
0.062364 | m^{3} torr mol^{-1} K^{-1} |
Factor | Variable | Units |
---|---|---|
Pressure | P | Atm, Torr, Pa, mmHg |
Volume | V | L, m^{3} |
Moles | n or $\nu$ | mol |
Temperature | T | K |
See the full table in this Wikipedia article
Unit | Symbol | Value of $p_A$ in these units | Value of 1 Pa in these units |
---|---|---|---|
Atmosphere | atm | 1 atm | $9.86923\times 10^{-6}\,$atm |
Millimeter of Mercury | mmHg | 760 mmHg | 0.0075 mmHg |
Torr | torr | 760 torr | 0.0075 torr |
Pascal (SI Unit) | Pa | 101325 Pa | 1 Pa |
Kilopascal | kPa | 101.325 kPa | 0.001 kPa |
Pound per square inch | psi, psia (“absolute”) | 14.696 psia | $14.5\times 10^{-5}\,$psi |
notes14.pdf – please download before class!
Download in MS Word format here: ch_17_equations.docx
A xxx-kg ice cube at 0.0 ^{o}C is dropped into a Styrofoam cup holding yyy kg of water at zzz ^{o}C. (a) Find the final temperature of the system and (b) the amount of ice (if any) remaining. Assume the cup and the surroundings can be ignored. (c) Find the initial temperature of the water that would be enough to just barely melt all of the ice.
Find the contents of the insulated container into which 1 ton of steam at 100 $^\circ$C and 1 ton of ice at 0 $^\circ$C were inserted.
Steps:
3 moles of xenon are heated to 400 K at atmospheric pressure. Find volume.
1 m^{3} of steam at 100$\,^\circ$C is compressed to 0.7 m^{3} at constant temperature. Find pressure and the amount of water (liquid) in the chamber.
Find the amount of heat released by condensing 1 oz of liquid water from steam.
Steps:
100% efficient 700-watt microwave oven is trying to warm up 1 pound of ice, initially at $-4\,^\circ$C.
Steps:
Find the spring constant of a steel cable 1 cm in diameter, and 100 m in length. How much will this cable stretch when lifting a load of 1 metric ton? Assume the Young's modulus of steel to be $\Upsilon_\text{steel}=20\times 10^{10}\,\frac{\text N}{{\text{m}}^2}$.
Steps:
notes15cor.pdf – please download the corrected version!
notes16.pdf – please download before class!
20 L of xenon at 25$\,^\circ$C and 1 atm of pressure are compressed to 19 L
Find work done by the compressor and the amount of heat released in each case
A quick summary can be downloaded here: lecture_16_problem_solution.pdf
Steps:
The cycle 1-2-3-4 performed on a monoatomic gas consists of:
Find the net work by the gas in the cycle and the efficiency of the heat engine based on it, if the lowest temperature in the cycle is 298 K.
Steps:
Gasoline in a certain engine is combusted at 1000 K, and the exhaust comes out at 400 K. Assuming the laws governing thermodynamic closed cycles apply here, what is the maximum efficiency that this engine can have?
Steps:
An ideal heat pump operating on a Carnot cycle in reverse consumes 1 kW from the electrical grid. How much heat per unit time does it supply to keep the inside of the house warm (at 25$\,^\circ$C) during a frigid winter day at 0$\,^\circ$C outside?
Steps:
One can be found here : ph202_final_equation_sheet.pdf
Another compilation can be found here : notes-15-18.pdf
— Nicholas Kuzma 2014/03/16 14:26