Homework

- Reading Preparation
- Key Equations
- WebLecture
- Study Activity
- Chat Preparation Activities
- Chapter Quiz
- Lab Work

**Text Reading**: Giancoli, *Physics - Principles with Applications*, Chapter 2: Sections 1-5

*Section 1:*We measure position from something, usually a point called our origin, against some background scale or frame of reference that tells us how far and in what direction. Distance alone from the origin will not give us location. We must also use directions (usually by measuring position against a coordinate system) to locate one point with respect to another. In mathematics and physics, quantities with only magnitude (size) are*scalar*, while quantities with both magnitude and direction are*vectors*. We perform mathematical operations such as addition and subtraction on scalars as we do in normal arithmetic. Vectors have their own rules for mathematical operations, since we have to take direction into account.*Section 2:*Displacement occurs over time when an object changes its location. If we consider only the total distance covered in a given period of time, we can calculate average speed. If we consider only the original and final position or displace, we can calculate average velocity.*Section 3:*A moving object has an instantaneous speed which cannot be directly observed or measured. To handle values at a given instant, we must use limits and calculus (technically beyond the scope of this course, but we'll look at it a bit in the AP section).*Section 4:*Any change in the velocity of an object is acceleration. Since velocity has two components, magnitude (speed) and direction, acceleration occurs if an object changes direction under constant speed (such as an object moving in a circle), as well as if the object speeds up or slows down.*Section 5:*The relationships of displacement, velocity, and acceleration can be summarized in four equations (remember that these assume*constant*velocity).

$$\begin{array}{l}v\text{}=\text{}{v}_{0}\text{}+\text{}\mathrm{at}\\ x\text{}=\text{}{x}_{0}\text{}+{v}_{0}t\text{}+\text{}\text{\xbd}a{t}^{2}\\ {v}^{2}\text{}=\text{}{v}_{0}^{2}+\text{}2a(x\text{}-\text{}{x}_{0})\\ {v}_{\mathrm{avg}}\text{}=\text{}\text{\xbd}(v\text{}+\text{}{v}_{0})\end{array}$$

**Read the following weblecture before chat**: The problems of distance and time

The study activities homework may include simulations you should try or other activities to help you understand how the concepts you are studying work in the real world.

Optional websites are just that: optional. You may check these out or not as you chose, but if you are having problems with concepts in the chapters, these sites may help you.

- The Introduction to physics lectures at Bellevue College provide further examples of each of the topics in this chapter. You should review any areas where you feel uncertain of the concepts.
- The NIST (National Institute of Standards and Technology) is in charge of monitoring and publishing formal definitions of standard units.
- There is a companion website for Giancoli,
*Physics: Principles with Applications*(sixth edition). You may find some of the features at this site useful in providing practice problems, questions, and (somewhat dated now) notes on applications. This site is no longer maintained, but at least it is still freely available. With edition seven, Pearson went to a "Mastering Physics" online course support system which requires students purchase additional access. I have not required that you get access to this site, since we have Moodle exercises that accomplish similar tasks with greater security.The Physics Tutoring Site has a page on Measurements that deal with mechanics.

**Essay question**: The Moodle forum for the session will assign a specific study question for you to prepare for chat. You need to read this question and post your answer**before**chat starts for this session.**Mastery Exercise**: The Moodle Mastery exercise for the chapter will contain sections related to our chat topic. Try to complete these before the chat starts, so that you can ask questions.

- The chapter quiz is not yet due.

If you want lab credit for this course, you must complete at least 12 labs (honors course) or 18 labs (AP students). One or more lab exercises are posted for each chapter as part of the homework assignment. We will be reviewing lab work at regular intervals, so do not get behind!

**Lab Instructions**:Velocities of Falling Bodies 1

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