Section

  • activity Monday:  find a value for g using available equipment

    HW due Tuesday: report a value for g from your experiment

    HW due Wednesday:  Bring solution to the problem assigned on Tuesday.  

    Thursday: we will measure moving objects: fan cart, ball, falling filter, etc

    HW due Friday:  Read the entire Wikipedia entry for "physics" and be prepared to answer questions.  Don't memorize dates and names, but absorb the main themes

    HW due next Tuesday: text problems chapter 1:9,19 (difficult), 22, 25, 53 and 1 other 2-dot problems.  

            also Tuesday: individually, use loggerpro to show me displacement, time, velocity, and acceleration for each movement

    HW due next Friday: give a 4 minute tour of your section of lab equipment

    Objectives for this week:

    • Understand the goals of this course

    • Explain how the pace and approach in the course will differ from last year

    • Apply your deep and long dormant knowledge of measurement and kinematics

    • show that you can be independent learners

    https://imgs.xkcd.com/comics/laws_of_physics.png

  • Due Tuesday: text problems chapter 1:9,19 (difficult), 25, 31, 43 and 1 other 2-dot problems.  also Tuesday: individually, use loggerpro to show me displacement, time, velocity, and acceleration for each movement

    in class: we will drop things and record their path with loggerpro.

    Due Wednesday: Hand in ramp analysis as assigned on Galileo Lab 

                in class you will design and conduct a lab to find g with a free falling object.

    Due Thursday: 2: p-3, 5, 15, 19, 27, 37, 41

    On Thursday: ARRIVE EARLY, 12:45 PM TO START LAB: bring prework assignment see attached lab "Find g as Galileo did"

    Due Friday:  Hand in short analysis of Tuesday Ball-drop demo as a HW problem; report the settings you used in Loggerpro, and carefully report the set up.  handwitten is fine.  Include a sketch of each set up.  The writing should be about a page long, and attach your loggerpro graphs that gave you acceleration.

    Also due Friday: give a 4 minute tour of your section of lab equipment

    Due next Monday: bring g data from lab.  2: P-53, 55, 63, 69, have latest Loggerpro available at home computer.  See tools for download instructions.

    Due  next Friday:  Lab 1 (galileo) Report due: 2 page memo, including photo, table of data (you must process and display data using Excel), sketch showing dimensions, propagation of error, comments on results, and suggestions to improve.

     Points:

    • Detail how calculus adds to our def’n of velocity and acceleration
    • Be able to determine v or x from an equation of a
    • Interpret classic plots relating x, v, and a as fct of time
    • Assess recall of motion graphs through review activity (5to5 p 80)
  • I've posted a correct answer key to ODD problems in FILES; some of your books may be wrong in the solutions appendix.

    Due Monday: bring g data from lab 1.  2: P-53, 55, 63, 69, have latest Loggerpro available at home computer.  See tools for download instructions.

    Due Tuesday:  Barrons chapter 2, MX exercises 3,4,6,7 and FR 2,3,4 (As I said, you need to purchase Barrons Study Guide 4th Ed.  Bring me $15 today and I will order one for you)
    Also due Tuesday: give a 4 minute tour of your section of lab equipment

    Wednesday:  Hand in short report of Ball-drop lab 1 as a HW problem; report the settings you used in Loggerpro, and carefully report the set up.  handwitten is fine.  Include a sketch of each set up.  The writing should be about a page long, and attach your loggerpro graphs that gave you acceleration.

    Due Thursday: 3: Q-7, 9; P-35, 44,  and do two 2-dot problems of your choice, and data analyzed from Lab3 for discussion  

    Thursday: evaluate and test next steps in Galileo ramp lab.

    Due Friday:  Lab 1 (galileo) Report due: 2 page memo, including photo, table of data (you must process and display data using Excel), sketch showing dimensions, propagation of error, comments on results, and suggestions to improve.   I have posted the grading rubric in FILES.  I will follow this when I grade the lab

    Due Next Monday:  F = G M1 M2/r        This is the equation for a model that describes the dollar volume of trade between two countries, F, as a product of a constant G, the M (size of economy) of each country) and the inverse of the distance, r, between the countries.    Does the form look familiar?  Find a physical reason why the denominator is r and not r2.

    read http://what-if.xkcd.com/62, and then find by web research a relationship between sphere size/mass and terminal velocity in air.  Specifically, you should be able to show how big a spherical balloon must be to slow your terminal velocity to 10.m/s.  See figure below.  This problem is not for fun, there are good answers and you are expected to find one using accepted physics.  Why?  Because understanding drag through air is an important part of this year, and independent learning is a critical part of your life.

    next week: we'll do lab on Go Motion and Video analysis with coffee filter

    * goals for this week:

    1. Detail how calculus adds to our def’n of velocity and acceleration
    2. Be able to determine v or x from an equation of a
    3. Interpret classic plots relating x, v, and a as fct of time
    4. Assess recall of motion graphs through review activity (5to5 p 80)

    figure 1.  Sketch of person mass m falling at terminal velocity vt using spherical balloon of negligible mass.

  • Due Monday:  F = G M1 M2/r       This is the equation for a model that describes the dollar volume of trade between two countries, F, as a product of a constant G, the M (size of economy) of each country) and the inverse of the distance, r, between the countries.    Does the form look familiar?  Find a physical reason why the denominator is r and not r2.

    read http://what-if.xkcd.com/62, and then find by web research a relationship between sphere size/mass and terminal velocity in air.  Specifically, you should be able to show how big a spherical balloon must be to slow your terminal velocity to 10.m/s.  See figure below.  This problem is not for fun, there are good answers and you are expected to find one using accepted physics.  Why?  Because understanding drag through air is an important part of this year, and independent learning is a critical part of your life.

                          In class, we will learn about drag of the filter (powerpoint slides)

    Due Tuesday:  2:MX 5,8 and FR 1,5

    Due Wed: 4 P-1,8, 9, 15, 17, 21  .Lab 3: freefall with Go Motion and Video analysis with coffee filter.   Refer to my discussion of drag and the physics of drag

    Thursday:  RETREAT

    Due Friday: RETREAT

    Due next Monday: 4: P39, 65, 63, 67, 107a, show the loggerpro analysis of all of your data in a table of terminal velocities (for the filters).  Turn it in (I'll give it back).

    Due next Tuesday.  bring your terminal velocity data plotted in Excel to find n and k.

     Points

    • Be able to solve problems in ijk vector notation
    •  Be able to identify parabolic relations and recognize parabolic motion
    • Be able to identify sin/cos relations and recognize circular motion
    • Be able to identify relative motion and solve in vectors

    galileo (Gal)

    the CGS unit of acceleration. One galileo is an acceleration of 1 centimeter per second per second (cm/s2). This unit is used by geologists, who make careful measurements of local variations in the acceleration of gravity in order to draw conclusions about the geologic structures underlying an area. These variations are typically measured in milligals (mGal). One Gal is approximately 0.001 019 7 g, where g is the acceleration of gravity, so a milligal is a very small acceleration, about 10-6 g. The name of the unit honors the Italian astronomer and natural philosopher Galileo Galilei (1564-1642), who proved that all objects at the Earth's surface experience the same gravitational acceleration. To avoid confusion with the symbol for the gallon, and to conform to the usual metric style, the symbol for this unit should be Gal rather than gal.

    Hey remember that cool cartoon on the Higgs?  Here's one on gravity waves, which were discovered last year.. http://www.phdcomics.com/tv/?v=4GbWfNHtHRg 

    And a reward for those who read all this entry: 

    www.youtube.com/embed/2rjbtsX7twc?list=UUTev4RNBiu6lqtx8z1e87fQ

  • the answer key to odd problems is posted in FILES.

    Due Monday: 4: P39, 65, 63, 67, 107a, show the loggerpro analysis of all of your data in a table of terminal velocities (for the filters).  Turn it in (I'll give it back).

    Due Tuesday: for review: 1. What launch angle will give R = hmax in a projectile motion "on the level" cannon;  2. What car velocity will allow a banked turn of 90o for a given radius, m, and μ?  3. What turn bank angle is necessary for a frictionless track for given r, v, m of car? 

    Due Wed: 5: Q-2, 4, P-12, 53, 71  (always bring Barrons to class)

    Due Thurs: show completed graph of F vs vn; complete all parts of AP-C Mechanics 2010 FR1 found here:    http://apcentral.collegeboard.com/apc/public/repository/ap10_frq_physics_c_mech.pdf.

    Due Friday:  turn in Barrons FRQ1 p 100. choose AP FR problems that have kinematics and/or force problems.   Do a total of 6 letter parts.

    Due next Monday: Exam 1, up through chapter 5

    some optional practice for the exam: 

    1. (10 points)   I drop a bowling ball of 5.4 kg from a tall cliff, and it reaches terminal velocity according to this equation for speed:
                          v = 850 (1-e-7.5t
      where t is time in seconds, and v is in m/s
      1. What is the terminal velocity?
      2. What is the distance travelled by the ball before it reaches terminal velocity?
      3. How much heat energy is dissipated by the ball before it reaches terminal velocity?

    A comment on report writing:

    • I'm raising the bar on your writing. We will do a bunch of reports of various types, and you will graduate from this class quite comfortable with writing good lab reports. That is my goal. So far I can see that reports and writing need some work, and I will hold the standard high.
    • Why?  Because convincing others that you know what you're talking about is of key importance. And most of your serious communication will be written.
    • A few common issues I see:
    • 0.  Narrative writing for reports means sentences and paragraphs.  It is telling a story with words.
    • 1. define any variable you introduce. e.g. Fg = the force of gravity on the puck; Θ is the angle between the table and the horizontal.
    • 2. any title for table or figure is a description of what is included. "Figure 1. Photo of sloping table with puck and detector in place"
    • 3. Learn how to make greek symbols and super and subscripts. It's not hard; don't use s^2 in place of s2
    • 4. Look for effects or results beyond those required. Show some curiosity. The world loves curious people.
    • 5. Always give a suggestion for improvement. You are being paid to think and make things better. Show that you have learned from your efforts.
    • 6. Take care when you write.   It requires 45 min for me to write a memo.  It probably will require you 2-3 times that long.  

  • Due Monday:   Exam 1 in class.  it will cover through chapter 5

    Due Tuesday:  I will hand out and we will discuss Lab on Projectile Motion  6: P-60, 68, and a 3-dot problem of choice; Barrons chapter 4 MX 1-5.  

    due Wed: 6: Q1,3,5 P-19, 23, 59 .  

    due Thursday:   Exercise in linearizing... that was handed out:  Complete parts 1-4

    due Friday:     Barron's 4: mx 6-8, fr 2,3   

    Due next Monday:    We will perform the projectile motion lab.   
    A car driver going at some speed v suddenly finds a n infinitely wide wall at a distance r in front of her. Should she apply brakes or turn the car in a circle of radius r to avoid hitting the wall?  You should assume there is a constant coefficient of friction with the ground.  Note: you have enough info and there is a definitive answer.  It should take about 3 lines of calculation.

    Due next Tuesday:  do AP 2000 Mech 3, and ignore the inertia of the pully    1. What launch angle will give R = hmax in a projectile motion "on the level" cannon;  2. What car velocity will allow a banked turn of 90o for a given radius, m, and μ?  3. What turn bank angle is necessary for a frictionless track for given r, v, m of car?   

    Next wednesday:  chapter 7: P-3, 5, 7, 9, 11

    Optional challenge that no one has every really tried to solve: find the function of the line defined by the outer envelope of motion of a given projectile cannon over all possible angles. look at this physlet and vary the angle from horizon to horizon to see the "envelope".    http://phet.colorado.edu/en/simulation/projectile-motion

    We'll look at the amazing Diavolo in class.

    activities: Quiz and practice 5:P-72 a,b and Problems 1,2 of Patel p39 (look under files)

  • Due Monday:    We will perform the projectile motion lab.   
    A car driver going at some speed v suddenly finds a n infinitely wide wall at a distance r in front of her. Should she apply brakes or turn the car in a circle of radius r to avoid hitting the wall?  You should assume there is a constant coefficient of friction with the ground.  Note: you have enough info and there is a definitive answer.  It should take about 3 lines of calculation.

    Due Tuesday:  do AP 2000 Mech 3, and ignore the inertia of the pully    1. What launch angle will give R = hmax in a projectile motion "on the level" cannon;  2. What car velocity will allow a banked turn of 90o for a given radius, m, and μ?  3. What turn bank angle is necessary for a frictionless track for given r, v, m of car?   

    Due wednesday:  chapter 7: P-3, 5, 7, 9, 11 

    Due Thursday: none Lab 4, projectile motion, video data analysis is due.  The video files are in j: drive, and you should confirm the launch velocity with the high speed video (210fps)

    Due Friday: 7; P-19, 23, 27, 29, 35.

    Due next Monday: finish the data analysis for the projectile motion lab
    AP problem 2009 Mech 1; 7: P-45, 47

  • Due Monday:  AP problem 2009 Mech 1; 7: P-45, 47

    Due Tuesday: velocity data for the lab; show me all the range data and all the speed data.

    Due Wednesday: 8: P-6, 23, 25, 27, 28; Choose one AP problem from the AP website that requires Energy for solving and be prepared to present to class  

    Thursday and Friday:  CONFERENCES

    Due next Monday: 8: Q 6-9; P-34, 40, 84;    practice in class 2000 M2

  • 8: Q 6-9; P-34, 40, 84;    practice in class 2000 M2

    Due Monday:  Lab report on projectile motion:    

     I will introduce elevator lab, Lab 5, due Nov 11. 

    Due Tuesday: 8: P-35, 57, 65, 121; we'll practice 2001M1 & 2002M3 in class

    Due Wednesday: 9: P-5, 3, 9   Barrons Chpt 6    Practice exercises MX #5 and FR#4 (two masses and a spring)

    Due Friday: group informal presentation on how data will be collected and analyzed for elevator lab.  Come prepared.  (you should have preliminary data to show it will work.)

    Due next Monday: 2003 Mech 2 and 1999 mech 1; chpt 9: P-32, 51, 67, 75, 79, 113 (be prepared to present)

    Due next Tuesday: choose one section of the projectile lab which you didn't do or did worst on, and rewrite it by today.  Turn in all parts of the lab with it.

    Points for this week:

    1. master energy problems as chapters 7 and 8
    2. master linear momentum problems as chapter 9

    "There are two types of people in this world: those who can extrapolate from incomplete data."

  • Due Monday: 2003 Mech 2 and 1999 mech 1; chpt 9: P-32, 51, 67, 75, 79, 113 (be prepared to present)

    Due Tuesday: choose one section of the projectile lab which you didn't do or did worst on, and rewrite it by today.  Turn in all parts of the lab with it.

    Due Wednesday: exam 2 in class,  it will emphasize all material since exam 1, but is cumulative as well.

    Due Thursday:  https://www.pivotinteractives.com/activities/59808f4039b10200111adbbb/preview 

    Due Friday: 9: P-63, 71, 101, (31 optional).     and show the calculation for Vo from the ballistic pendulum 

    Due next Monday: 1. Do the famous "chain problem" for a frictionless chain of length L, mass M. Show that the velocity after it has passed length x over the edge is v= x(g/L)1/2 and show that acceleration is a=(x/L)g (note, you don't need calculus for these).  Also find the time t necessary for the chain to leave the table top (assuming it starts with 1/3 of chain over the edge).  Also do AP 2009 M3. It's very similar.

    • Last week was the birthday of rocket scientist Robert Goddard, born in Worcester, Massachusetts (1882). Goddard had been interested in outer space since he read H.G. Wells' The War of the Worlds when he was 16. He started thinking seriously about rockets the following year, in 1899.
    • He received a patent for his design for a liquid-fueled rocket in 1914, and another for one that ran on solid fuel.  He raised some money to do research and publish a paper on "A Method for Reaching Extreme Altitudes" in 1920. In the paper, he speculated that rockets could be used to reach the moon.
    • The New York Times heard about his paper, and published an editorial ridiculing him that a rocket couldn't work in a vacuum. He went from "nobody" to "national laughingstock" literally overnight, but he said, "Every vision is a joke until the first man accomplishes it; once realized, it becomes commonplace." He didn't give up, and on this date in 1926, he completed the first successful launch of his liquid-fueled rocket in Auburn, Massachusetts. The rocket reached a height of 41 feet and an average speed of 60 miles per hour.
    • Unfortunately, Goddard didn't live to see space flight become a reality; he died of cancer in 1945, and Sputnik was in 1958. In July 1969, the day after Apollo 11 departed for the Moon, The New York Times printed a correction to its scathing editorial of nearly 50 years before. The paper wrote, "It is now definitely established that a rocket can function in a vacuum as well as in an atmosphere. The Times regrets the error."
  • NOTE: I found two practice books that show all of the released AP FR and MX questions.  Look in FILES for these.

    Due Monday: 1. Do the famous "chain problem" for a frictionless chain of length L, mass M. Show that the velocity after it has passed length x over the edge is v= x(g/L)1/2 and show that acceleration is a=(x/L)g (note, you don't need calculus for these).  Also find the time t necessary for the chain to leave the table top (assuming it starts with 1/3 of chain over the edge).  Also do AP 2009 M3. It's very similar.

    in class:  practice ap2011m1, ap1979m1

    Due Tuesday:   have your elevator data and analysis ready and understood, we will discuss it.

    Due Wed:  find and complete an AP problem that includes rotation.  2013M3 for example.  

    Thursday:10: P-82, 83, 85, 87, 95   practice 2017M3 and 2015M3

    Due Friday: Elevator lab is due;   We will discuss how the presentation will be divided.

    Due next Monday : introduce ping pong lab--how to take v data and get n;  10: P-45, 53, plus Barrons chpt 7: Free Response 1-4

    Plans this week: review Giancoli chapter 8 classics: chapter 10 in text or chapter 7 in Barrons.

  • WE ARE A FLIPPED CLASSROOM.  YOU REVIEW AND LEARN AT HOME, WE PRACTICE AND CLARIFY IN CLASS.

    Due Monday:  10: P-45, 53, plus Barrons chpt 7: Free Response 1-4  

    IN CLASS: finish HW, and 

    solve the toilet paper drop problem (one roll is freely dropped, one roll is unrolled during the drop; what speed will each hit the ground from 2m?  What ratio of heights will allow each roll to hit the ground at the same time?  Measure a roll or assume a radius, and assume they are a solid cylinder)

    Due Tuesday: 10: P-82, 83, 85, 87, 95, Barrons Chapter 7 MX 1-5.   Also due is the assigned summary of the presentation from Friday.  Toan and Oliver will summarize the results on the assigned method at the U elevator, Petros and Alejandro will summarize their alternate method (pendulum or kinematics?), and Ian will summarize his data for the school elevator.

    Due Wednesday: FINALS

    watch this video on frames of reference.....watch at 13 min to end to 25 min learn about Fictitious Forces and Noninertial Frames   http://archive.org/details/frames_of_reference

  • Welcome to Term 2.  Stay focused please, there is much material to cover, and we will pick up speed.

    Over New Years break, you have a reading assignment.  Don't panic, it is fun reading, but with some work.  See FILES Physics of the Impossible.

    Due Monday: none, we'll review final exam; also discuss the ping pong lab schedule.    Are we done with angular momentum?

    Due Tuesday:AP 2004 M2.   

    Due Wed:  find an AP problem that requires angular momentum to solve

    Due Thursday: read chapter 11; problems 10: P-101; and 11: Q-1,2,3,4,5;

    Due Friday:  

    Due next Monday: 11: P-5, 11, 12, 9, and find string angle on spool for static pull.   Your preliminary analysis for the lab, including all calculations for 1-4, is due today.

    Due next Tuesday: 11: P-35, 41, 92     A ping pong is shot from our cannon at 280 m/s and strikes the end of a plastic meter stick that is pivoting vertically by the other end.  The ball bounces off elastically.   what is the velocity of the stick just after the collision?  how far (what angle) does the stick swing?  what is the period of the stick as it swings?  how fast does the ball rebound from the collision?  I wouild like a symbolic answer to each and a numeric (you will have to collect some data about the objects)

    In class this week: 1986M2

    19th century rap......The Pirates of Penzance

    I am the very model of a modern Physics-General,
    I've information static, kinematic, and dynamical,
    I know the Laws of Newton, and I quote the men historical
    Einstein, Galileo, and the rest all categorical;
    I'm very well acquainted, too, with matters mathematical,
    I understand equations, even be they quadratical,
    About binomial theorem I'm teeming with a lot o' news,
    With many cheerful facts about the square of the hypotenuse.

    I'm very good at integral and differential calculus,
    I know the scientific names of beings animalculous;
    In short, in matters vegetable, animal, and mineral,
    I am the very model of a modern Major-General.

    Slightly adjusted from Sir W.S. [William Schwenk] Gilbert born in 1836 on Nov 19

     

  • Due Monday: 11: P-5, 11, 12, 9, find string angle on spool for static pull, as demonstrated in lab, and as discussed in Q3 of chapter 9.   Your preliminary analysis for the lab, including all calculations for 1-4, is due today.

    Due Tuesday: 11: P-35, 41, 92     A ping pong is shot from our cannon at 280 m/s and strikes the end of a plastic meter stick that is pivoting vertically by the other end.  The ball bounces off elastically.   what is the velocity of the stick just after the collision?  how far (what angle) does the stick swing?  what is the period of the stick as it swings?  how fast does the ball rebound from the collision?  I wouild like a symbolic answer to each and a numeric (you will have to collect some data about the objects)

    Due Wed: 11: P-54, 77, 81 (do symbolically, and also find a and α), 91;  Barrons 8: FR1, 2 and Barrons 8: MX1,2,3. 

    Thursday: we will do the ping pong lab in class.  know all parts of the operation, and I'll assign them when you arrive. 
    And this challenge question that you should at least set up the strategy for.  Some smart students are exploring the outer perimeter of a castle. They notice a spy hole in its wall, across the moat a horizontal distance x and vertically up the wall a distance y. They decide to throw pebbles at the hole. One girl wants to use physics to throw with the minimum speed necessary to hit the hole. What is the required launch speed v and launch angle θ above the horizontal?  Note that this is NOT the classic where there pebble hits the hole at the top of the parabolic curve.  TPT 55, 528

    Due Friday: ap 2001m3, ap2016M3 

    Due next Monday: 11: P-87, 71, 61; AP2003FR3   Loggerpro velocity profiles of all ping pong runs.  Show me V vs. x plots for each run and slope for a of deceleration for each run.

    Wednesday: work on Barrons chapter 8:  FR 2, 4, and 3  

    Points:

    1. 1.Understand the parallel axis theorem, apply to rotation problems
    2. 2.Rolling, torque, and angular momentum
    3. 3.Find the applications of calculus to angular momentum problems
    4. 4.Be able to design a simple lab to text P-8 and conduct it

  • Due Monday: 11: P-87, 71, 61; AP2003FR3   Loggerpro velocity profiles of all ping pong runs.  Show me V vs. x plots for each run and slope for a of deceleration for each run.  You should show a linear fit to calculate acceleration, and be selective and smart about what part of the plot you fit to linear.  

    Due Tue: do this FR question.



    Due Wed: 12: P-1, 5, 25, 23, 35 ,33, 37  check this out 

    http://gfm.aps.org/meetings/dfd-2014/5404ec5f69702d0771a40100

    Due Thurs:  Professor Paine will present.  Solve the statics problem done on Tuesday and compare predicted to measured tension.  If the entire operation was on a cart that accelerated at 2.0 m/s2,  what is the predicted tension?

    Due Friday:   No class, BUT.... Written report of PingPong Lab, part 1 is due.  Formal report, all sections.  see below 

    Due next  year, 2 January 2018:    A mirror reverses left-right but not up-down.  Why is that?  Even more, if you lay sideways, now left-right is up-down, and the mirror figures that out.

    PingPong Lab: 

    Hypothesis for part 1: we can measure the acceleration of the ping pong ball for a range of velocities and summarize all the data in an Excel table (run, pvacuum, avg vslowing, aslowing)

    Report: due Friday, 15 Dec.  Formal report, all sections.  Should be brief.  For procedure, assume we know how the ping-pong gun normally works.  Need photo of entire setup and photo of measured zone.  (can't use screen shot from video, it's too grainy).  Include all Loggerpro graphs with linear fits for acceleration (if you yourself don't do a given video analysis, you must list on the graph who did it).  Include Excel table of data.

    COMMENTS: 1. if the hypothesis is to find acceleration, then it's important that you show and describe how to get a.  You must include the graph of loggerpro, and describe how to use v vs. t to get a.  2. "propagation of error" was asked for, which means propagate an error into the final answer.  an example would be initial pressure, or mass of ball

  • Due Tuesday:  A mirror reverses left-right but not up-down.  Why is that?  Even more, if you lay sideways, now left-right is up-down, and the mirror figures that out.

    Due Wednesday: 

    Due Thursday:  Lab on rotational dynamics, in FILES and handed out

    Due Friday: 13: P-9, 13, 23, 25, 31; Barrons 10: MX questions 1-4;   AP 2014 Mech 3

    Due next Monday:   Physics of the Impossible Slides are due, and you will present today.  Patel mechanics exam 1: 13, 16, 28, 31, 35 (this is posted in FILES) In #31, how do you differentiate between a collision and an external torque?

    goals this week

    1. get back up to speed so we can make a lot of progress in this, our long stretch without breaks
    2. apply universal gravitation to bodies in orbital motion
    3. show me that you understand gravitational potential energy, a rather complicated concept.
    4. explain to me why as the moon's orbital velocity slows with time, it moves away from the earth and stays in stable orbit.

    Feedback in grading for the PingPong Lab part I.  

    • On the website I told you we can assume we know how the ping-pong gun normally works. So there is no need to going to details about how to shoot the ball.
    • But for this lab, capturing the proper video was an important part for you to describe.  So I expected information about the placement of the camera placement of the lights and running the video during the shot.
    • Similarly, in the material section you needed to say something about the camera at the model the speed and about the bright lights used. 
    • Then in the analysis part I expected you to comment on the odd shape of the velocity curve and how you used only the latter part after the air stop pushing the ball.  
    • I'm not going to accept rewrites, but you can come see me for clarification on any of this.

  • We are going fast and I'm assigning a variety of HW. To help you become mature learners, here is my advice: be selective and smart about which HW problems to do.  If I assign a long assignment, then select the 4-6 that are most helpful to you.  If you don't do any, then that just means you get a HW check.  But if you smartly pick the ones that help you learn and practice, then you're exams will go fine.

        Here's is a funny video about a guy who is too dependent on his equation sheet.  

         http://www.nytimes.com/video/opinion/100000004115589/verbatim-expert-witness.html?smprod=nytcore-iphone&smid=nytcore-iphone-share 

    Due Monday:   Physics of the Impossible Slides are due, and you will present today

    Due Tuesday :  13: 37, 35, 43, 53, calculate how far into Earth we would descend to reduce g by 10%. 
                      discuss the potential energy inside a planet.  See notes in FILES.

    Due Wednesday:  13: 61, 73, AP1999M2, and Barrons 10: MX questions 5-8. 

    Due Thursday: do the 1984 section of the MX problems.  35 questions.  located in FILES as CMC84mech

    Due Friday: 15: P-17, 23, 25 how long will day last if Earth rotated so fast that g=0 at the equator, P-33, 35, 41 , 51, 54

    Due next Tuesday:   Ping Pong Lab part 2.  This is a formal report, but since it is the "theoretical" portion of the lab, you can omit sections 4 and 5 in the guidelines.  You should use and report the consensus data, and explain where that came from.   Give credit to everyone else by name.   You can reference your part 1 report, but this report should stand on its own; for example, reprint any data tables from the first report that you are using.  you do not need to show the loggerpro graphs from the first report.

    Due next Wednesday: 15: P-77, 79, 91, 73, 95, 93   Look at this 15-minute TED talk.  This is what you should be like: skeptical of claims.   http://www.ted.com/talks/ben_goldacre_battling_bad_science.html  Most bad science is in the area of health and nutrition.  Can you explain why?

     discuss exam 1 = 11 Multiple Choice problems at 3 points each + You choose 11 Free Response sections (letters) at 4 points each.  (topics are rotation, rotation, & SHM) You must clearly circumscribe with a box each section of your work and the answer that is to be graded.  I cannot and will not fish around looking for something that looks related.

    Practice: 2001 M2; 1995 M3

  • Look at this 15-minute TED talk.  This speaker is a model of good scientist: he is skeptical of claims.

    http://www.ted.com/talks/ben_goldacre_battling_bad_science.html

    Most bad science is in the area of health and nutrition.  Can you explain why?

  • Due Tuesday:   Ping Pong Lab part 2.  This is a formal report, but since it is the "theoretical" portion of the lab, you can omit sections 4 and 5 in the guidelines.  You should use and report the consensus data, and explain where that came from.   Give credit to everyone else by name.   You can reference your part 1 report, but this report should stand on its own; for example, reprint any data tables from the first report that you are using.  you do not need to show the loggerpro graphs from the first report.

    Due Wednesday: 15: P-77, 79, 91, 73, 95, 93   Look at this 15-minute TED talk.  This is what you should be like: skeptical of claims.   http://www.ted.com/talks/ben_goldacre_battling_bad_science.html  Most bad science is in the area of health and nutrition.  Can you explain why?

    Look at this 15-minute TED talk.  This is what you should be like: skeptical of claims.   http://www.ted.com/talks/ben_goldacre_battling_bad_science.html  Most bad science is in the area of health and nutrition.  Can you explain why? 

    Due Thursday:   AP 1990M3  Review for exam

    Due Friday: exam 1 in class.  it will cover rotational dynamics and oscillations (linear, not rotational).  

    • 13  Multiple Choice problems at 2 points each.
    • 2 FR at 15 points each

    Due next Monday: 21: P-7, 12, 21 

    Due next Tue: Rotational dynamics lab presentation in class

    goals for this week: complete the basic mastery of oscillations.  work through all MX and FR in Barrons oscillation chapter.

    next week: handout and discuss our next lab; complex pendulum motion
    and speaking of angular momentum, watch this video   and be prepared to discuss (I like this Smarter Every Day guy)

  • Due Monday: 21: P-7, 12, 21,    review exam.

    Due Tuesday: Rotational dynamics lab presentation in class.  Each group must be ready.  It will cost points to be late.

    Due Wednesday: 21: P-23, 35, 53,49, 25      do complex pendulum data in class

    Due Thursday: 

    due  Friday: do one AP-C free response related to chapter 21.    

    Due next Monday : Lab pendulum: bring your video analysis of the data --  Explain how you will extract data for "k" of the spring and "L" of the pendulum.
         chapter 12 problems from Barrons -- Practice exercises Barrons 12 MX 1-6; FR 1-2; bring the calculations for total mechanical energy of the pendulum at the beginning and at the end

    Due next Friday: memo report for complex pendulum

    We are plowing through charge and fields with the help of Barrons.

    1. we are starting electricity.  You are responsible to review the fundamentals of charges, coulomb's law, and the basic material of chapter 21.

    we will review this in class by reviewing the problems

    topics covered:

    problem 21 in detail.  then practice on this:  cylinder of radius r1 to r2 and with rho = br2.  what is Q?  Then do cube of size 40cm, with rho = 2r in one dimension.

    problem 23 in detail.  then practice on this: charge +q is position y above the origin.  Find E(y) for fixed position X on the x axis.  Sketch and plot before any math is done.

  • Due Monday : Lab pendulum: bring your video analysis of the data --  Explain how you will extract data for "k" of the spring and "L" of the pendulum. 
    chapter 12 problems from Barrons -- Practice exercises Barrons 12 MX 1-6; FR 1-2; bring the calculations for total mechanical energy of the pendulum at the beginning and at the end

    Due Tuesday: do the FR question below from 1986

    Due Wednesday: show me your answers to the 4 questions in the complex pendulum lab;  AP 2011 E&M 1, AP 2010 E&M 1; quiz on one of these

    Due Thursday: section 24-5 and 24-7; section 24-9: P-31, 35, 40, 7

    Due Friday:   24: 23, 63, 79

    Due next Monday: lab report on pendulum

    practice

    problem 21 in detail.  then practice on this:  cylinder of radius r1 to r2 and with rho = br2.  what is Q?  Then do cube of size 40cm, with rho = 2r in one dimension.

    problem 23 in detail.  then practice on this: charge +q is position y above the origin.  Find E(y) for fixed position X on the x axis.  Sketch and plot before any math is done.

    Points:

    1. Show how to derive field for points, lines of charge, shapes of charge

    2. Show how to derive potential for points, lines of charge, shapes of charge

    3. Demonstrate how Gauss’ Law allows fields around charge distributions other than point charges

    1986 FR1

    1.  Three point charges produce the electric equipotential lines shown on the diagram above.

    a.   Draw arrows at points L, N. and U on the diagram to indicate the direction of the electric field at these points.

    b.   At which of the lettered points is the electric field E greatest in magnitude? Explain your reasoning.

    c.   Compute an approximate value for the magnitude of the electric field E at point P.

    d.   Compute an approximate value for the potential difference, VM ‑ VS, between points M and S.

    e.   Determine the work done by the field if a charge of +5 x 10‑12 coulomb is moved from point M to point R.

    f.   If the charge of +5 x 10‑12 coulomb were moved from point M first to point S, and then to point R, would the answer to (e)  be different, and if so, how?

  • Due Monday: complex pendulum lab report 

    Due Tuesday: chpt 13: FR1 from Barrons, p 397   

    Due Wed: read 23 sections 4-9; 23: P-19, 21, 25, 29, 37, 49

    Due THurs: do 2 of these FR's:  AP 1990E&M 1; AP 1999 E&M 1;  2004 E&M 1

    Friday: quiz on Gauss’s Law, potential, and E fields.  we'll do 1980E1 in class for some review

    Due next Monday: 25: P-7, 17, 19

    NOTE: once you get your pendulum labs back, please schedule 10 min with me to discuss your pendulum analysis by 17 Feb.  Bring your lab and any supporting docs.

    Mon: more line integrals practice

    Tue: what happens when conductors are used--look at the shell problems

    Wed:  more Gauss and line of charge E problem

    Friday: review of 22-24 chapters problems    practice: sphere radius a.   rho = r3/4.   sketch charges and field lines.  find E for each zone.  Find V at edge (radius a).  Find V at center compared to edge.  Plot E and V vs. position

    summary of key steps in all problems.

    1. draw physical setup
    2. add representative +/- charges at correct ratio
    3. add E field lines for each +/- charge drawn
    4. observe where E is zero, and where it higher or lower
    5. sketch a rough sketch of E given your view
    6. use Gauss to find exact relationships for E
    7. integrate to find ΔV and carefully consider limits for V2 and V1
  • Review page 37 of course description to learn meaning of words on page 37+

    Due Monday: 25: P-7, 17, 19

    HW due Tuesday: 25: P-3, 7,13,  35, 53.  

    Due Wed:  do 3 Barrons FR problems on Gauss

    Due Thurs: exam 2 in class.

    Due Friday: no class  

    Due next Monday: no class  

    Due next Tuesday:25: P-21, 25, 19, and AP 2002 E&M 2

    Points:

    • practice 2003 EM1 (tough, but nice.)
    • Understand what a capacitor does: stores charges separated by distance, requires work to separate them
    • Know how to calculate C generally using Gauss, then V = - then C= q/V
    • Follow the charge to understand how capacitors in circuits will behave

     

  • This section

    http://robotics.nasa.gov/events/livestream/index.php?stream=ntl_0225-2815

    Due Monday: no class

    Due Tuesday: 25: P-21, 25, 19, and AP 2002 E&M 2

    Due Wed:    AP 2014 a-d

    Due Thurs:    Barrons Mechanics Practice Test 1; MX problems (as in any problems with the answers available, you should do them each to your best ability, and use the answer to check your work.)

    Due Friday:  26: P-11, 26, 35, 54, 59, 39, 73, 71. 

    The Final Exam has 29 MX and 3 FR questions.  Balanced mech and E&M.  Rotation, gravity, oscillation are good things to review.

    practice problems:

    1)   I want to launch a satellite mass M into a stable orbit at 3REarth. (above the center of Earth, mass ME).  a)  what is final v of satellite?  b)  what is potential energy at this altitude?  c)  how much work must the rocket do to lift and accelerate the rocket?  d)  what is the total energy at this altitude?   e)  now if I remain in stable orbit, but decrease the altitude, what happens to total E and to U and K?

    2)   an equilateral triangle of mass M and side L hangs by its vertex.   a)  what work is needed to rotate it to horizontal position?  b) If then let go, what will ω be when it is back to starting position.  c)  what will period of the oscillation be?

    3)  for a certain gravity field, U=r3.   a) what is the shape of the PE curve?   b) what is the force at r = a?