Mr. Rogers' IB/AP Physics I: Mechanics Objectives Syllabus 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Circular Motion Linear Momentum Rotation Statics Gravity

Chapter 10: Rotation p. 292

 Standards Assessments Practice Test Study Guide
 Objectives

Section 10.1, 14.2

1. State the rotational equivalents of the linear quantities mass (p. 301, see table 10.2 on p.304), velocity, acceleration, and force (p.306).

2. State the 2 types of vector multiplication and describe the differences between them.

3. For rotational inertia or moment of inertia, state the dominate effect, distance fro the center of rotation or mass.

4. Convert between various methods of expressing rotational velocities.

5. Indicate which rotational quantities are vectors and which are scalars.

6. Use the right hand thumb rule to represent rotational vectors as arrows where the length is proportional to the magnitude and the arrow head represents the direction. (Figure 10.3, p. 295)

7. By looking at the arrows representing rotational velocity and acceleration, determine if an object's rotation is speeding up or slowing down.

8. By looking at the arrows representing rotational acceleration determine the direction of the arrow representing the torque vector.

9. Solve problems with rotational kinematics equations.

10. Calculate rotational kinetic energy.

Homework: Questions 1-5 Problems 1, 3, 7. Serway

Metacognition Problem Solving Principle 10.1: For every linear motion equation and principle there is a rotational counterpart. In other words if you know the equations and principles of motion in the linear world you know them in the rotational world.

 Activities

Lesson 1

Key Concept: Every quantity and equation in the linear world has a counterpart in the rotational world.

Purpose: Enable students to write rotational equations, given linear equations addressing similar situations.

Interactive Discussion: Objective 1-8. List the linear and their corresponding rotational quantities on the board.

Demo 10.1:  Objective 1, 400 grams of mass taped on the end of a meter stick. Have students balance the mass on their hand first with the mass close to the hand and second with the mass as far as possible from the hand. Which way is easier and why?

In Class Problem Solving: Objectives 9 and 10

1. State the Earth's rotational velocity in RPM, RPS, tangential velocity, and w.
2. Spin down time on a wheel.
3. Swinging door problem. q = 2t^3 - 3t^2 +5t + 7, Find q, w, a  @ t=10 sec
4. Calculate the rotational kinetic energy stored in Earth both in joules and megatons of TNT.

Resources/Materials: Meter stick, tape, and 2, 200 gram weights.

Section 10.3

1. State the two key equations which link the linear and rotational worlds.

2. Given a wheel's w solve for its linear velocity and vice versa.

3. Given a wheel's a solve for its linear acceleration and vice versa.

4. Find the net torque on a wheel.

5. Use the rotational version of Newton's second law. (See example 10.9, p.307.)

6. Calculate the max torque which can be exerted on a wheel without making it spin.

7. Solve yo-yo problems.

8. Solve pulley problems. (See example 10.12, p.310.)

9. Calculate the acceleration of the free end of a rod which rotates around a fixed pivot on one end as it falls. (See example 10.10, p.309.)

Metacognition Problem Solving Principle 10.2: There is an equation which links the linear world to the rotational world for every property of motion in physics. The three most useful ones are shown below:

 1) v = rw 2) a = ra 3) t = (F) x (r)

Homework: prob. 33, 35, 37, 59 Serway

 Lesson 2Key Concept: There are three key equations which link the linear and rotational worlds. Purpose: Show how rotation and linear motion interact. Interactive Discussion: Objective In Class Problem Solving: Objectives  See objectives 12 to 19
 Section 10.3 Solve swinging rod problems. Solve yo-yo problems using conservation of energy. Calculate the power required to turn a winch. Solve belt problems. Homework: prob. 45, 47 Serway
 Lesson 3Key Concept: Rotational Work, Power, and Energy Purpose: Apply conservation of energy to rotational problems Interactive Discussion: Objectives 11 to 14 In Class Problem Solving: Objectives 11 to 14 See objectives 11 to 14.
 Formal Lab Investigation Title Investigation of a Belt Drive Category Mechanics Purpose Determine if the belt on a 5.25 inch floppy disk drive is slipping. Models V = r(w) Overview Use a strobe light to measure the rotational velocity of the wheels in a floppy disk drive. Safety Issues Do not flash the strobe in anyone's eyes. Do not short circuit the power supplies. They can burn up. Do not touch any pieces of rotating equipment. This can seriously injure fingers. Equipment Limitations The floppy drives can be damaged if run too fast for a long period of time.