Richard

//Teacher Name//:**Richard Doherty** //Email//:(Call or txt me) 917-733-3144 I'll let you know if I can't talk right then. I do not stay up past 10:00 pm. I do not do email or chat. They are impersonal, slow and certainly non-interactive. Texting is just as bad, but I can handle it when I have my hands free. //Homework Policy//: Homework MUST be attempted ON THE NIGHT IT IS ASSIGNED! There is no such thing as "making up homework." Homework is both a measure of how much you understand and a trigger to make you recognize where you need more explanation. If you come to class without having tried the homework, you are wasting your time and the time of the rest of the class. By trying the homework you are primed to understand the solution as we go over it in class. Homework is never graded for correctness - only for your having attempted it. That means it is useless for you to copy it.

Algebra, calculus and arithmetic are the languages of Physics. Make heavy use of [|TheMathPage] (__//http://www.themathpage.com//__)

**Current Homework:**
During the storm disaster week and before Monday, November 5:

Let’s not lose momentum (pun intended)! You have an excellent opportunity to spend some quality time with the problem set I gave you, and you have lots of time to pore over the textbook. To that end, I submit the following: Your constant reading assignment is Section 2-7 (pp. 31-35). Once you’ve done your three readings, spend some time going over the following paragraphs (annotated by me):

P. 31 – all five paragraphs. Galileo brought humankind out of total ignorance that had lasted 3000 years. He was a brave soul, and, even though he founded the Scientific Method and literally all of modern science, he ran afoul of the church and was confined to his residence for the last ten years of his life. Anybody that brave (and willing to make mistakes, as I keep advocating) deserves your undivided attention. He was the first to understand the idea of approaching perfection so he could //think// about ideal motion (as we do in high school physics) and ignore secondary effects (friction for one). Read this section with respect!

P. 32 and 33. This simple statement (top of page 32) was arrived at by Galileo by using his mathematical predictions. You should know that the mathematics of the time depended heavily on geometry and some geometric relationships we have forgotten in modern times. Galileo did not have the benefit of most of the algebra you know today! That would have to wait for Isaac Newton, who was born the year Galileo died (and 301 years before I was born!). He went on to perform numerous experiments over his lifetime and still publish his findings – even though they contradicted what the church said about the relationship of the Earth to the universe. The example problems are just wonderful. Try to do them on your own after reading them once. Then go back and correct your mistakes. Try them once again. Correct your mistakes. Remember: //Reading// about a Big Mac is just not the same!

P. 34. Conceptual example 2-13 attacks the main stumbling blocks we physics teachers face year after year. Pay attention. Utter either one of these during a college interview and you’re out. Example 2-14 proves the idea that a ball thrown upward will have the same velocity reversed as it passes the throwing point on the way down. Even if you do not believe this, memorize it! You will eventually see how simple the concept is.

P. 35 The Quadratic Formula. Show of hands – how many thought the quadratic formula was only for math tests? It really is necessary, and there is really a meaning for the two roots you get when you use it. I can’t get this across in this simple missive, but I will drive it home when we come back. Math is central to so many subjects, that I am dismayed by the attitudes I see as a teacher.

I will cover pages 36 and 37 when we can look each other in the eye; it’s the basis for calculus!

I hope to see you Monday. I hope you are all well and did not suffer from the storm effects.

/*########################################################################*/ Special for Friday, October 26: There was some confusion today over what to do in the lab. Think tonight about where you had problems. The problems I saw were: 1. Refusing to use fractions - using inexact decimals instead. Fractions are exact; learn to use them. Understanding fractions is central to solving problems in physics. 2. Measuring in inches. 3. Not realizing that you need tow velocities to compute an acceleration. PS> I still can't figure out what one group did to get 500 something m/s/s. I used their data and got 990 cm/s/s or thereabouts. Please try to detect your error tomorrow. So, I'm not giving the quiz tomorrow, Friday. It will be Tuesday, and it will be regents questions, and it will include interpreting a position graph, a velocity graph and a paper tape with little dots on it - just like the one you made today. I fixed the sparker. /*##########################################################################*/ for Thursday and Friday, October 25-26: Attempt problems 35 and 36 without looking at your notes from today. Then try 37 and 38. Remember: repetition without immediate checking on previous notes is vital to building confidence in problem solving. We will conduct a lab exercise on Thursday. The theme will be falling objects, and we will emphasize getting velocity and acceleration from position information only. Next week or this Friday I will give you your first quiz - after presenting you with a worksheet from which I will select the quiz questions. /*##########################################################################*/ For Tuesday and Wednesday (October 9 and 10): Be experts at the three graphs on the problem set. Remember: you are sketching, not making a prize-winning graph. You could do the graphs using Excel, and that would assure me that you understand what you are doing. Just getting the formulas correct is rewarding. However, in Excel you will need to understand which points in time each value represents. For example, calculating the average velocity from t = 0.5s to t = 0.75s //implies// that the point in time at which you report that velocity is half-way between the two end times. That is 0.625 seconds. Now that's a complication //unless you're sketching//. If you are sketching, we're only interested in the shape of the curve. It still needs to be accurate, but the absolute time reference is of less importance than the graph slope (approximate) around each data point. Remember that you are learning to "speak" physics, and physicists talk with math and graphs as easily as they do with words. We are leading up to Thursday's lab where we'll look at some real-world motion, velocity and acceleration.

Test Phrase: Acceleration is not velocity. /*##########################################################################*/

For Friday (October 5): Read __Section 2-4__ ( pages 23, 24 and 25) on __Acceleration__ 3 times at least. Be sure to stop in between readings and try to summarize it before you read it again. Please remember that the //concept// of acceleration is one of the most difficult first concepts in Physics. Most people do not understand it at all at first. Don't be surprised if you have trouble at first. Later on, you will wonder what was so difficult. Also, hand in your lab reports. It's important that you do them as soon as possible after the lab time. If you wait too long, the learning part turns into just "filling in the blanks", which is useless.

Test phrase: Violets are flowers

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Problems 6 and 8 on Page 39. Due in the first 5 minutes of class on Thursday, September 27. We need the rest of the time for a lab. Problem 6 is essentially review. Remember to try to do it all in one expression - not in pieces. Also, you will have an easier time if you solve it algebraically first and then substitute the values. If you use parentheses when you substitute, you will not make a mess of the signs. Problem 8 involves conversion of units. You should use 1 mile = 1.6 kilometers. You'd better know how many meters in a kilometer by now. I strongly suggest you set this one up as a long string of factors that will give you meters per second from seconds per mile. This is a skill you must develop - and soon.

Test phrase: The sky is blue.

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Due: Monday, September 25 Work Problems 1, 2, 3, 4 and 5 on page 39 of your textbook (Chapter 2). Be sure to apply the techniques we discuss in class; your old methods are a dead end. I don't know why everyone else seems to let you get away with "knowing" the answer.

Problem 4 will require you to use some outside information. I prefer that you learn unit conversions, because if you just "look it up" on the internet, you will have learned only to push buttons and copy numbers from a screen. "What I cannot create I do not understand." -Richard Feynman

When you do these problems, do every step on paper. Don't skip anything. If you still need to "divide both sides by t" or something like that, do it on paper. If you don't have all the steps there, you can not tell where you made a mistake.