General College Physics

Wisconsin Lutheran High School

Week 10

Reading: PSE Chap 7, Work and Energy

Topics: This week, we begin discussing the concepts of work, kinetic and potential energy, energy conservation, and power

Lab:

Homework Problems: Due on Wed. Oct. 26.

Sled on a pond: Solution. A sled of mass m is given a kick so it is sliding across a frozen pond at an initial speed of 2 m/s. The coefficient of kinetic friction between the sled and the ice is 0.10. Using energy considerations, find the distance the sled moves before coming to a stop. Hint: the friction force is doing work on the sled.
Climbing gymnast: Solution. A 50 kg gymnast climbs a 10 meter high vertical rope in 5 seconds. Find the average power output of the gymnast in climbing the rope.
Work on a particle. Solution. A 4.0 kg particle is moving along the x-axis. Its position varies according to x(t) = t + 2.0 * t^3. x(t) is in meters and t is in seconds.

Find the kinetic energy at any time, t. Hint: use calculus.
Find the acceleration and the force acting on it at time t.
Find the power delivered to the particle at time t.
Find the work done on the particle in the time interval between 0 and 2 seconds.

Spring gun: Solution. A spring gun is used to launch a stainless steel ball straight up into the air. The spring constant is 10 Newton per centimeter. The spring is compressed 2 cm. Assume the ball weights 100 grams and that the spring itself is massless and frictionless. What is the muzzle velocity of the ball at the moment it leaves the gun? Hint: the change is kinetic energy is equal to the -net- work done on the ball. There are two forces doing work on the ball. Now: how would your answer change if the gun is aimed at a 45 degree angle? Is the muzzle velocity the same?

Quiz: We will have a quiz on Monday, Oct. 17 covering Newton's laws of motion, including friction, drag, and centripetal force.

Mid-term grade estimation: I will be curving the grades for AP physics. I am still trying to figure out how to do this using on-campus grading without just adding points to your current grades. So here is how you should estimate your midterm grade. Look at your current on-campus grade. If you are currently scoring

above 95%, you are currently getting an A+
above 90% you are currently getting an A
above 80% you are currently getting a B+
above 75% you are currently getting a B
below 75% you are currently getting a B-

General College Physics

Return to course website.

Course syllabus

Physics: The world around us is in a state of constant change: the sun and moon rise and set, waves crash, mists rise, rain falls, fires burn, rocks form, and mountains crumble. Amidst all of these changes, there are certain patterns; there is a discernible order. In other words: the stars, the seas, the clouds, the rocks, and the earth itself each seem to have a particular nature. Physics is the careful study of the natures of things. In fact, the word physics literally means "natures" in the Greek language.

Course overview: General College Physics is a year-long introductory course for advanced (typically junior or senior level) students at Wisconsin Lutheran High School who want to better understand the natures of the things we see around us. It is a dual-credit course offered at Wisconsin Lutheran High School in collaboration with Wisconsin Lutheran College. For a detailed overview of the topics we will be covering, refer to the course website (www.greatphysics.com) and the tentative calendar on the following page. Emphasis on theoretical topics, careful thinking, laboratory experiments, and problem solving makes this course challenging. My aim is to help you succeed in this course, and to have fun while learning physics. So please do not hesitate to contact me with any problems you may run into this semester!

Advanced Placement credit: While this is not designated as an AP course, students students have successfully taken the AP Physics test at the end of the year for college credit.

Course textbook: The course will be organized around a book: the Pocket Guide to accompany Physics for Scientists and Engineers (4th edition) by Serway. (I’ll call this PSE for short.) I would highly recommend obtaining a copy of this book. It is inexpensive, compact, and well-written. It will make a very handy addition to your home science library. If you don't want to buy it, I will have copies to loan out for the semester.

Course time and location: The course meets every day (Monday through Friday) during the academic year from 2:16 until 3 pm in WLHS 223—in the science wing on the first floor of WLHS. On late start days (such as Wednesdays) the course begins at 2:24.

Professor: Dr. Kuehn from Wisconsin Lutheran College (WLC) is the professor for this course. Contact info: kerry.kuehn[at]wlhs.org

Teaching Assistant contact info: The Wednesday course sections (beginning in September) will be overseen by two teaching assistants. Alyssa Ebeling and Zeke Micheel are upper-level physics majors from Wisconsin Lutheran College. Here is their contact info: alyssa.ebeling[at]wlc.edu, ezekiel.micheel[at]wlc.edu

Course websites: In addition to the course information provided through WLHS’s OnCampus system, we will be also using a website I’ve designed for this course: www.greatphysics.com/AP1/

Homework exercises: I will assign weekly homework problems. These are designed to deepen your understanding of lecture material and to prepare you for the quizzes and tests. I do not intend to grade your homework solutions; I will merely give you credit for handing in your best attempt by the due date. Please refer to the late work policy for more details.

Laboratory exercises: Some of our weekly assignments will include laboratory work. Labs will typically take up at least two class periods. Your laboratory notebook pages must be submitted by the assigned due date. More details about the required format and expectations will be discussed before the first laboratory period. You will need to order/purchase a dedicated laboratory notebook. Here are guildlines on what to include in your laboratory notebook.

Quizzes: We will have in-class quizzes almost every week on Monday. To prepare for quizzes, you should read the assigned book chapter (at least once), review the lecture material, complete all of the homework problems, and review the homework solutions.

Tests: We will have a midterm exam before the end of the first (and third) quarters and a comprehensive final examination before the end of the second (and fourth) quarters.

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