Homework

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

**Text Reading**: Giancoli, *Physics - Principles with Applications*, 5: 1-3

- 5.1
*Circular Motion; Gravitation*. Now we start putting things together. Circular motion can be described in terms of kinematics (motion). This section shows how the relationship of circular motion can be derived mathematically by understanding the relationship between*centripetal*and*tangential*velocities, and between*angular*acceleration and*linear*acceleration. The repeated motion allows us to use concepts of*periods*and*frequency*. - 5.2
*Dynamics of Uniform Circular Motion*. Circular motion can also be described in terms of dynamics (forces).*Centripetal*force is the real force that pulls an object inward toward the center. There is no real*centrifugal*(outward) force. - 5.3
*A Car Rounding a Curve*. Study the diagrams of forces acting on a car on a "flat" curve and a banked curve, and be sure you understand why banking increases traction.

Small angle approximation for change in velocity during circular motion:

$$\frac{\Delta v}{v}\text{}=\text{}\frac{\Delta l}{r}$$Small angle approximation for acceleration during circular motion:

$$a\text{}=\text{}\frac{\Delta v}{\Delta t}\text{}=\text{}\frac{v\text{}\Delta l}{r\text{}\Delta t}$$Radial acceleration:

$${a}_{R}=\text{}\frac{{v}^{2}}{r}$$Period

$$T\text{}=\text{}\frac{1}{f}\text{}$$Circular velocity in terms of period

$$v\text{}=\text{}\frac{2\pi r}{T}$$Force required to keep a body moving with circular motion: $$\sum {F}_{R}\text{}=\text{}m{a}_{R}\text{}=\text{}m\text{}\frac{{v}^{2}}{r}$$

Banking speed

$${F}_{N}\text{}\mathrm{sin}\text{}\theta =\text{}m\text{}\frac{{v}^{2}}{r}$$**Read the following weblecture before chat**: Circular Motion

The Gravitron was one of my favorite carnival rides. You can simulate the forces of the ride in Gravitron. See if you can determine the minimum coefficient of static friction required to keep an object in place.

Physics at the University of Boston.

**Forum 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**: Centripetal Force

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