Unit Four: Advanced Topics in Forces

Dec. 2 - Jan 8
Goals
Be able to add forces in two dimensions.
Understand and apply conditions for equilibrium.
Calculate the frictional force when given the coefficient of friction and vice versa.
Determine the normal force, and the parallel and perpendicular components of gravity for inclined plane problems and solve for acceleration.
State and apply equations for centripetal acceleration and force.
Distinguish between the centripetal force and the fictitious centrifugal force.
Analyze examples of circular motion in terms of Newton's three laws of motion.

State and apply Newton's universal law of gravity.

Important Activities

Friction Lab : due Dec. 8

Unit Test: Jan 7 and 8

Homework:

12/5: Read pp. 151-154, write lab report, due 12/8

12/8: Read pp. 130-133

12/9: Problems p133 : 14-15; p146: 33-35; p154: 5, 7, 8; and concept development sheets 5-3 and 5-4

12/10: Read 163-166 concept development sheet 9-2

12/12: Problems p172: 49, 50, 51, 54

12/15: Read pp. 175-192

12/16: Problems p.195: 35, 37, 39, 40

12/17: Moons of Jupiter Lab Calculations and problem p. 195: 4

1/5: Review Sheets

Web Support:

Use the link on the right for great tutorials about inclined planes, circular motion and gravity.

Moons of Jupiter simulation

http://www3.gettysburg.edu/~marschal/clea/juplab.html

Unit Three Description

Sorry. This should have been put up a month ago.

Goals
Draw Force Vectors.
Calculate Weight.
Solve Problems with Net Force.
Know that when an object is at rest or moving with constant velocity that that Fnet = 0 and all of the forces are balanced.
Understand what terminal velocity is and how it is reached.
Be able to explain why all objects in freefall have an acceleration of 9.8 m/s2
Understand that forces are interactions between two things and that each object exerts an equal and opposite force on the other.
Know Newton’s Three Laws of Motion by name.
In general, understand Newton’s 3 laws and apply them to explain motion.

Test Date: Nov. 18
Lab Due Date: Nov. 5 (6 for period 5) Drafts of sections due at earlier dates. See lab handout.

Homework:
Due date Assignment
Tues,10/28 p. 144-145, Q 3,10
Fri, 11/7 Problems with Newton’s Second Law and Q 25, 27, 29, 32, 36
Fri, 11/14 Q 11, 19

Solutions to Additional Problems for Newton's Laws

1. 60,000 N
2. 150 N, yes the bag lifts it without breaking.
3. The elevator accelerates him upward at 2.5 m/s2, then travels with a constant velocity, and then slows while traveling upward at a rate of 3 m/s2.
4. 5 m/s2
5. 133m/s2, 3,325 N, 250 N, unlikely - the driver would have to exert a force that is 13 x greater than the child's weight and react in a tenth of a second
6. At all times the propeller pushes backwards on the water and the water pushes forward on the propeller. There is also a big resistant force on the front of the boat: the boat pushes the water forward and the water pushes the boat backwards. When the boat travels at constant speed (and with no acceleration) the forces between the propeller and the water must be equal to the resistive force on the front of the boat. When the boat is accelerating the propellor must push harder causing the water to push harder on the back of the boat and producing a net force forward on the book. When the propeller is turned off, the boat slows down, because there is now a net force backwards afainst the velocity. This occurs bbecause the re is still warer resistance pushing backward on the boat, but no longer a forward force due to the propeller.

7. While it is true that the forces between the propeller pushing backward on the water and the water behind the boat (propeller) pushing forward on the boat (propeller), these forces do not cancel each other resulting in zero net force. These forces don't cancel because they are on different things - the water and the boat. Similarly, the water pushes the boat backward when the boat pushes the water forward as it pushes through the water. These forces also don't cancel each other becasue they are on different objects - the water and the boat.. The boat travels at constant speed, because the two forces on the boat (from the water resisting in front, and from the water pushing on the propeller in the back) are qual and opposite to each other.

8. If the earth pulls on a satellite with 1000 N then the satellite pulls on the earth with 1000 N of force. The force does not affect the path of the earth through space because the acceleration resulting from 1000N divided by the enormous mass of the earth is next to nothing.



9. 200 N (forces are balanced becuase the velociy is constant) The friction force is equal and opposite to the push resulting in 0 net force, but it is not the reaction force. The reaction force to your pushing the refrigerator is the refrigerator pushing on you. The reaction force to the floor pushing on the refrigerator with friction is the refrigerator pushing on the floor.



10 When you weigh yourself on a scale, the scale pushes up on you as hard as you push down on it. Normally you push down on the scale with as much force as the earth pulls down on you with gravity, thus normally the scale reading is the same as your weight, the force due to gravity. If though, you push up on the bottom of the sink then you will push into the scale with more force, the scale pushes up with you for more force and the reading goes up. Similarly if you push down on the top of the sink then the sink will push up on you, supporting some of your weight and the scale will support less of your weight. You will push down less on the scale and the scale will push up on you less.

11. At a point halfway up the ball is moving upward because its inertia is causing it to continue the motion it has. It is slowing down because there is a single, unbalanced force on it - gravity - which is producing a downward acceleration against the velocity. On the way down, there is still a single force, gravity, that is now causing it to accelerate downward.

12. a. ball bumps head, bug hits windshield, ball hits bat, nose touches hand, flower pulls hand, bar pushes athlete down, balloon pushes air inward.

11.

Physics Online Tutorial

This looks like a great site for conceptual expanations. It also has problems with answers.
The Physics Tutorial.

For review over Thanksgiving holidays, you should look at the section called Newton's Laws.

Answers to physics homework due 11/7

Worksheet:
1. 2.5 m/s2
2. a. 50 N, b. 2.5 N c.
3. 0.3 m/s2
4. 600N
5. 15 m/s2, 30 m/s, 30 m

Book
25. 6300 N
27. 250 kg
29 10.5 m/s2 down
32 300 N, no
36 a. 1.04 m/s2, -0.633 m/s2,, c stopping

Answers to p79 27-32

27. 510 km, 79 degrees S of W
28a. 6.5 m/s, b. 6.5 degrees from vertical
29. 160 km/h at 18 degrees west of south
30. 5 km, 53 degrees south of east. You don't need to do this one with a diagram.
31. 5 m/s at 53 degrees from the shore. b. 3 m/s c. 4 m/s
32. 16 m/s at 66 degrees above the horizontal

Unit Two – Vectors and Kinematics in Two Dimensions

Covers Sections 4.1, 4,2 and 7,2

Unit Goals:
1. Know that perpendicular vectors are independent
2. Add vectors graphically with parallelogram and head to tail methods.
3. Use trig and Pythagorean theorem to find resultant.
4. Break vectors into perpendicular components graphically and with trig.
5. Solve motion problems in 2D.

Test - Tuesday Oct, 21

Assignments
Tues 10/7 Read sections 4.1 and 4.2; p. 78, Problems 23 and 24

Mon. 10/13 p. 78, Problems 27-32

Wed. 10/15 p. 172 Problems 40-43, 45, 47

Fri. 10/24 Hole in one lab solution write up.

Mon. 10/20 Review Problems

Solutions to problems 17-23 on p. 61 and worksheet

17. 20 m
18. 8m
19. 8.3 m/s
20. 33.75m
21. 44.6m
22. 7.3 m/s
23. 7.3 m/s

Worksheet: Instantaneous and Average Velocity Practice
a. 1 m/s
b. 1.4 m/s
c. 1.6 m/s
d. 0.6 m/s

Velocity Vector Addition

Unit 1

Unit 1: Kinematics in 1 Dimension

Goals:
1. Know and apply the definition for average velocity.
2. Know and apply the definition for average acceleration.
3. Differentiate instantaneous and average velocity.
4. Interpret graphs of position, velocity and acceleration, including through the use of slopes and the area under the graph.
5. Draw position, velocity and acceleration graphs for described motion.
6. Know the acceleration due to gravity.
7. Solve problems by using 5 basic mechanics equations.
8. Properly use sign conventions for positive and negative acclerations and velocities.
9. Describe sources of error as either random or systematic and suggest basic ways of reducing error such as controlling variables, doing multiple trials, collecting data over a wide range and using big sample sizes.

Homework: Due Date
Letter to Teacher & Safety Contract Fri, 9/5
Lab 1 data presentation Wed, 9/10
Understanding motion through graphs(wksht) Mon, 9/15
Lab 1 report Mon, 9/15 (Lab one handout) see also lab sheets in links on the right
Instantaneous Velocity…(wksht) Fri. 9/19
Bookwork Ch. 3 Problems (p. 61): 17-23 &
Inst. & Ave. Vel…(wksht) Mon, 9/22
Solving Problems in Phys(wksht) &
Intro to Accel (wksht) Fri. 9/26
Writing for Review Mon 9/29

Unit Test : Tuesday 9/30

Checking Grades

Here is a link to the Parent Assist website.
Many Grant teachers will use this district provided program to maintain and post their grades. You will also be able to monitor attendance and check personal information.
I will update grades after every major test and lab, but I might not get every late assignment or retake in the gradebook promptly.

To use this website you will need to get a personal code from the Grant High School office. The secretaries expect to receive these codes soon, but have not received them yet. I will update this post when they are available. If you have a code from last year or for any other child it should still be active.

http://parent.pps.k12.or.us/

Welcome Back & General Information

The 2008-2009 school year has started. Welcome to Physics.

Here is some general information about how the class runs.

Grades:
Approximately 50% Tests, 30% Labs, 20% homework

Tests: About twice a quarter, with semester finals also. Retakes are available, but only half the missed points are recoverable.

Labs: Although we’ll have weekly hands-on lab assignments, I’ll only have you write up formal lab reports about twice a quarter. (The first one will be due Sept. 15.) Late labs are penalized at 10% a week.

Homework: I’ll check them off for effort and completion on the due date and collect them in a packet on the test day. Show your work, be neat, stay organized. Talk to me if homework ever feels like busy work. No late homework accepted except for excused absences.

Grading Scale: 100-90 A, 90-80 B, 80-70 C, 70-60 D, <60 F.

Supplies:
Textbook
Notebook, or section of a notebook
Calculator
Protractor
Graph Paper

Passwords are Now Available

Passwords are now available for the Parent Assist website. From this website you can check grades if your child is in my or 14 other Grant Teachers' classes, check a complete attendance record and access other information. You can follow the link on the right for checking grades. The Passwords are available from the main office at Grant High School.
Please let me know if there are problems.

Grading software passwords

As of Feb. 26, the office at Grant does not have the passwords to access my students' grades. I will try to let you know when they do. I hope they get them soon.

Light Unit

Goals:
1. What is Light?
Be able to describe and give effective examples of the strengths and weaknesses of the two models of light.

2. How does light behave?
Reflection:
What is the law of reflection?
Be able to locate images and make ray diagrams.

Refraction:
What is refraction?
What is Snell’s Law?
How did we determine a law for refraction?
Be able to solve problems and draw ray diagrams.

Colors:
What are primary, secondary and complementary colors?
How are colors produced by dispersion, addition and subtraction of light?

Lenses:
Be able to draw ray diagrams for converging and diverging lenses.
Identify images as real or virtual.

Others:
Explain the production of rainbows and the color of the sky and sunset.
Summarize how diffraction and interference apply to light.

Assignments (tentative)

assignment (due date)
Reflection concept development sheets 29-1, 29-2 (2/28 )
Data tables and graphs for refraction lab (2/29 )
Refraction Lab report (negotiated)
Snell’s Law Worksheet (3/6 )
Color Concept Development Worksheet 28-1 ( 3/7 )
Testing a Particle Model of Light (3/13 )
Read Chapter 17 : Questions 31,33,41,42,54,57,58 (3/17 )
Lens Worksheets (3/20)
Review Handouts (4/3 )

Unit Test April 4

My New Grading Software

This semester I will be using the grading software that is a part of the software that the district uses for attendance and grade reporting. You will still be able to check grades on-line and may be able to view grades for several classes at the same site: such as Mr. William's grades. To access the grades and all of the attendance and demographics information on the site, you will need to get your username and password from the office at Grant. It will only be issued to the parent or guardian and, I assume, only with identification. More and more teachers at Grant are beginning to use this grading program and although it may be a nuisance to get the id codes, in the long run, it will make staying up to date with your child's grades much easier.
Here is a link to the web site http://parent.pps.k12.or.us/

Semester 2 Unit 1 Waves and Sound

Goals:

1. Explain what a wave is.
2. Differentiate between longitudinal and transverse waves.
3. Correctly use the vocabulary: medium, pulse, crest, trough, compression, and rarefaction.
4. Define and apply the following wave characteristics: period, frequency, velocity, wavelength, amplitude, energy
5. Apply the following: T=1/f and v =f*wavelength
6. Explain how standing waves are produced and correctly use the terms nodes and antinodes.
7. Explain the following wave behaviors, interference, beats, resonance, doppler effect and sonic booms.

Homework:
2/7 (due 2/8) read 14.1 answer questions on p.335, practice problems 2,3,5,6
2/8 (due 2/12)read 14.2 and 15.1 Answer the questions:
p. 345 Q 16,17,18, and p.346 Q 42
p. 369 Q 13,14, 16, 18, 19, 42
Wave Superposition Practice Sheet
(Mon, 2/11 will be a work day)
2/12 read sec. 15.2

2/14 (due 2/18)Speed of Sound Lab Questions
(Fri, 2/15 will also be a work day)
2/18 (In class) Wave Review work sheets

Test Fri, 2/22
On Thursday 2/21 we’ll do an activity for the next unit on light.

The great website http://www.kettering.edu/~drussell/demos.html