#Goals: SWBAT...
1. ... Explain energy transfer in circuits
2. ... Identify instruments and tools used in circuits
3. ... Solve problems involving current, potential, and power
WARM-UP:
1. Does an electron carry a positive, negative, or neutral charge?
2. When water begins falling off a waterfall, which two kinds of energy does it possess?
3. Copy the diagram of energy transfer from page 593.
a. List the flow of energy from start (waterfall) to finish (bucket moves)
b. How is energy lost from the system?
c. What does "Thermal Energy" mean in basic (layman's) English.
CLASSWORK:
1. Reading Quiz (last one!)
2. HW Review
- Video
- open (circuit not complete) v. closed (circuit complete (all connected))
- easiest path (parth of least resistance - aka most direct)
- conductor (metal, water) v. insulator (foam, rubber)
3. Electricity Notes
Coulomb: unit of charge. Symbol: C 1C=6.24x1018 electrons
Two kinds of charge: positive (+) and negative (-)
Electric charge is neither created nor destroyed. It is merely separated
Objects with a net negative charge have excess electrons
Objects with a net positive charge have a deficit of electrons
Water flows from high to low
Electric current flows from high potential to low potential
We measure electrical current in C/s, or Amperes (amps) (symbol: A)
4. The Tools of Electricity
For each item (1-6), individually complete the following...
Name:
Description of Physical Form:
How much it costs
Function:
HOMEWORK:
Copy the diagram of different circuit symbols (pg 597) into your notes. Search each term conductor, switch, fuse, etc [you can skip "electric connection and no electric connection"], and write the term and definition.
Introduction to Conventional Current
http://www.flippingphysics.com/introduction-to-conventional-current.html
0. What does "q" or "Q" stand for? What is the unit of q? What is I? What is the unit of I?
1. Why are the electrons the atomic components which flow, and not the protons?
2. Which way do electrons flow?
3. Why does that give us a positive direction of current flow?
4. Copy the current graphs.
A. Which do we use for long-distance electricity transmission?
B. Which do we use in our homes?
5. Copy the example problem
#Goals: SWBAT...
1. ...Stay focused on Physics
2. ...Prep for that final thingie
3. ...Stay focused on Physics
WARM-UP:
0. Bring your textbook and golden card on Wednesday (day of final)
1. Your textbook has a weight of approximately 10N (2.2lb). If you apply a force of 10N parallel to a 0.5m long lever arm (see pic on board -->), what torque will be applied?
2. What if the force is applied at an angle of 90* (perpendicular to the lever)? (see pic-->).
What torque will be applied?
3. Find the momentum of each car.
Car One has mass=1000kg, velocity of 20m/s to the left, and is driven by your 50kg grandma
Car Two has mass=750kg, velocity of 40m/s to the right, and is driven by 150kg Dwayne
Johnson.
What is the combined momentum of the two car system?
CLASSWORK:
1. Ohm's and Resistance Notes
- Resistance Definition: Resistance is the property of a materials ability to conduct electricity (aka, how easily the material allows current to flow).
- A resistance of 1Ω (Ohm) is the resistance that allows 1A (one amp) of electric current to flow when there's a 1V (one volt) potential difference between the two ends of the circuit.
- Examples of Resistance Amounts
Silver wire: 0.0000000159 ohm
Copper Wire: 0.0000000168 ohm
Car brake light: 3 ohm
Glass: 1,000,000,000 ohm
Rubber: 100,000,000,000,000 ohm
Your Mom: ∞
http://www.flippingphysics.com/defining-resistance.html
2. pg 598 6. Sketch the diagram, then solve the problem
3. Final Exam & Review
- Your test will cover:
CH 8.1; 8.2; 8.3
CH 9.1; 9.2
CH 10.1
CH 11.1; 11.2
CH 22.1
What you should study:
Vocab
Your notes & Warm-Ups
The Study Guides at the end of each chapter
Practice Problems:
CH 8 pg 869: 1, 2, 3, 5, 8, pg 224: 90
Answers:
1. 0.21 rad/s2
2. 0.31 m/s
3. 0.25m
5. 11Nm counter clockwise
8. 27kg
90. F(left)=3.6x102N
F(right)=1.4x102N
CH 9 pg 870-871: 1, 3, 7, Extra Credit: 10
1. 10kg m/s
3. 2.07 m/s
7. 1.3m/s west
10. ?
CH 10 pg 871: 1, 3, pg 279: 66
1. zero Joules
3. 1.5 x 102 N
66. 1.20 x 104J
CH 11 pg 872: 4, 6, 11
4. 1.3 x 105 J
6. 18m/s
11. KE is not conserved
CH 22 pg 881: 3, 6, 7
3. 21A
6. 8.33 Ohm
7. draw it
HOMEWORK:
1. Notes Sheet for final exam (one page front and back, or two single-side pages - due 05/27
I'll give some extra credit for completing the entire set of review problems (show your work) and for problem 10 from Chapter 9
2. You final exam will have two parts if you're a Junior, and one part (written only) if you're a senior (yippie!)
A. Written Portion. In Class on Wednesday 05/27
B. Lab Practical. In Class during finals period 06/01 (juniors only)