PHL100Y1 Lecture : Intro Lectures March 10

54 views3 pages

blushcaribou733

5 Apr 2011

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

It is mentioned in one of the chapters of the new lectures. Imagine that you"re a journalist for the globe and mail and you must write about this paper. You"re writing supposing the readers don"t already know about the subject. You don"t have to give your opinion but you can. Write in simple english as you would in the gandm. You can if you want, give your opinion. During that time, freud has changed his mind during this time. Prof is going to talk about two articles that freud wrote between two sets of lectures. Btpp was motivated largely by the problem that occurred during and after the war. It became a big problem on both sides of the war during wwi and wwii. One of the names for this is gulf war syndrome . It is soldiers who have witnessed a very traumatic event and they keep repeating this in their lives and in their dreams.

Related Questions

Consider three identical spherical conductors. One conductor,labeled A, is given a
charge of 7mC of type Nell. The charge state of the second andthird conductors, B and C, are unknown. The conductors undergo asequence of 3 contacts that occur ONLY between pairs of conductors.After the contacts, the net charge on each conductor is A: (0.25mCof type Nell), B: (1.875mC of type Nell) and C: (1.875mC of typeNell). Letâs make the assumption that the type Paul charge statecorresponds to an excess of electrons.

Because these three spheres are ______________________ the_______________ can be
freely exchanged between any pair of conductors in contact. Sincethese conductive
spheres all have the same size, when the spheres are placed incontact the ______
_____________ will evenly distribute between the two spheres.Because charge is a
property of particles and the particles can not be destroyed ANDthere is no outside
source of charge, the _______________ charge of the ______________must remain
constant at 4mC of type Nell. Based on this information, we candetermine that the
charge of at least one of B or C must be of type_______________.

To determine the order of contacts we must start from the lastcontact and work our way to the first contact. It is important tonote that because we have no initial charge state information forspheres B and C that we have the ability to make an arbitrarydecision about the initial charge state of these two spheres. Inother words, the charge states of sphere B and C areinterchangeable. Third and last Contact: Because spheres ________and _______ have the same charge we can determine that they were______ in contact. If we look at spheres B and C as the system, wefind that the total charge of the sub system consisting of B and Cwas ______________ of type _________.

Second contact: We can safely assume that A touched either B or Cprior to B and C
being brought into contact. Here we can make the arbitrary choicethat B touched A in the second contact. If this is the case, weknow that the charge of B ___________ it touched C must have been______________ of type __________ because it must have the sameamount and type of charge as the final state of _______. Therefore,at this instant we know that the charge on sphere C was________________ of type ____________________ it touched B.

First contact: Now we have an interesting situation. We find thatthe charge state of
sphere C would be consistent with sphere C being initially____________ and being
placed in contact with _______________ since the charge state of Cis exactly
__________ that of ____________ initially. This would mean that thecharge state of
sphere A after contact with ______ would be _____________ of type__________.
However, we already determined that the __________ charge of thesystem containing sphere _______ and sphere _______ in the secondcontact was ____________ of type __________. The only way this ispossible is if sphere B has a charge of __________ of type____________.

Final Results
The initial charge state of sphere Ais:_________________________________________
The initial charge state of sphere Bis:_________________________________________
The initial charge state of sphere Cis:_________________________________________
In the first contact of sphere ___________ to sphere_________________ how many
electrons were transferred from one sphere to the other?
In the second contact of sphere ___________ to sphere_________________ how many
electrons were transferred from one sphere to the other?
In the third contact of sphere ___________ to sphere_________________ how many
electrons were transferred from one sphere to the other?

Vapor cycles
5EM - Thermodynamics
September 2010
1 The T-S diagram
The temperature-entropy diagram is an alternative to the well knownpressure-
volume diagram. Before using it to analyze different vapor cycles,we need
to understand it properly.
1. Plot the following transformations for ideal gases in a T-Sdiagram
(a) Isothermal expansion
(b) Isobaric expansion
(c) Isometric heating
(d) Reversible adiabatic expansion
(e) Irreversible adiabatic expansion
2. Repeat the last question, but this time do it for a realsubstance,
starting in the compressed liquid1 region and ending in thesuperheated
region, when possible. Indicate the boundaries of eachregion.
3. We know that under certain circumstances the area under theplot
in a P-V diagram represents the work performed during theprocess.
What does it represent in this case? Under what assumptions isyour
answer true? Compare examples 6.1 and 6.2.
2 Thermal machines
We understand by thermal machine a device capable of transformingther-
mal energy (heat) into mechanical energy (work). We already knowthat
these machines have a limited efficiency which, in the two-sourcesmodel, is
obtained by Carnotâs cycle.
(Compressed liquid is sometimes also called subcooled liquid)
2.1 Carnot cycle
This cycle, although efficient, is impractical. To begin with, theextreme
temperatures of the cycle should be within the sources temperaturesfor a
finite heat flow to exist.
1. Given the temperature of the sources, draw the cycle accordingto the
named limitation.
2. Show that this leads to lower efficiency than the theoreticallimit.
3. Assume that heat flow from/to the sources is proportional to thetem-
perature difference between them and the working fluid, anddemon-
strate that a higher power output is related to a decreasedefficiency.
2.2 Rankine cycle
Out of the several practical possibilities, Rankine cycle and itsvariations is
widely used, especially for electric power generation.
1. Draw the basic cycle in a T-S diagram and explain it.
2. What does the efficiency of the cycle depend on? Comparewith
Carnotâs.
3. What are the differences between the ideal cycle and the realone?
4. Describe how it is modified by superheating and/or reheating.Explain
te benefits.
2.3 Problems
After answering the previous questions solve the followingexercises from the
book: 8.2, 8.4, 8.5, 8.13, 8.19, 8.20
3 Frigorific machines
3.1 Reverse Carnot cycle
We have already studied Carnot cycle in detail as the ideal thermalmachine.
Now we will take is as the starting point to understand thecharacteristics
of frigorific machines.
1. Draw the ideal cycle in a T-S diagram and explain it.
2. Show that this cycle has a theoretical efficiency Ã =Tcold/Thot-Tcold
3. What are the difficulties in implementing such cycle in actualdevices?
3.2 Actual refrigerators
1. Why is the turbine replaced by an expansion valve in mostcases?
2. Plot the actual cycle and explain the differences with the idealcase.
3. How do cascade and multistage systems improve the performanceof
the refrigerator?
4. What aspects are important in the choice of a refrigerant fluid?Justify
3.3 Problems
After answering the previous questions solve the followingexercises from the
book: 10.2 10.7, 10.8, 10.9, 10.22, 10.23 10.1D

1. If a car's wheels are replaced with wheels of greater diameter,will the reading of the speedometer change? Explain.

2. Weightlessness in space is known to have harmful effects on thebodies of people in space. To set up inhabitants (people) in space,it has been suggested that rotating cylinders about 10 miles longand 5 miles in diameter be placed in space. The purpose of theirrotation is to simulate gravity for the people so they have weight.Explain how this is possible?
000000000000000000000000000000000000000000000000000000000000000000000
Please use DragMath to submit the solutions to problems No. 5 and 6of Activity 9A on page 129 of Bendall & Howison.
0000000000000000000000000000000000000000000000000000000000000000000000000
1. Why do the string instruments go flat (lower frequencies) andthe wind instruments go sharp (higher frequencies) during aperformance if an orchestra doesn't warm up beforehand?
2. If you were carrying a fish tank filled with water, what willhappen if your walking frequency matches the natural frequency ofthe water in the tank?
Good luck with these questions. I look forward to a heartydiscussion by Friday this week.
000000000000000000000000000000000000000000000000000000000000000000000000
1. Household circuits are always wired so that the electricaldevices are connected in parallel. Why is this so?
2. How are circuit breakers connected in the household circuits(series or parallel)? What is the use of a circuit breaker? Why isit more advantageous to use a circuit breaker compared to using afuse?
Hope to hear your answers soon.
00000000000000000000000000000000000000000000000000000000000000000000000000
Mathematical Question:
Try the question on capacitors Activity 14C no. 3. You can useDragmath to submit your solution. If you are scanning your answersand uploading a file, please keep its size small.
Challenge Question:
A fully charged parallel-plate capacitor remains connected to abattery while you slide a dielectric between the plates. Do thefollowing quantities increase, decrease, or stay the same? (a)capacitance, C (b) charge, Q (c) electric field, E between theplates, (d) change in voltage, V (e) energy stored in thecapacitor.
0000000000000000000000000000000000000000000000000000000000000000000000
Twisted wires: In electrical circuits, it is often the case thatinsulated wires carrying currents in opposite directions aretwisted together. What is the advantage in doing this?
Have a go; looking forward to some interesting replies.
0000000000000000000000000000000000000000000000000000000000000000000000
Metal detectors in airports: When you walk through the doorway ofan airport metal detector, you are really walking through a coil ofmany turns, i.e. an inductor connected to a resonant circuit tunedto the resonant frequency when there is no metal in the inductor.So how does this circuit detect any metal that is in your pocketwhen you walk through the metal detector?
Looking forward to your replies.
0000000000000000000000000000000000000000000000000000000000000000000000

PHL100Y1 Lecture : Intro Lectures March 10

Document Summary

Get access

Related Documents

PHL100Y1 Lecture : Intro Lectures March 31

PHL100Y1 Lecture Notes - Pure Mathematics, Intersubjectivity, Neurosis

PHL100Y1 Lecture Notes - Lecture 2: John Stuart Mill, Jeremy Bentham, Experience Machine

Related Questions