Lecture Outline Chapter 10. Physics, 4 th Edition James S. Walker. Copyright 2010 Pearson Education, Inc.

Transcription

1 Lecture Outline Chapter 10 Physics, 4 th Edition James S. Walker

2 Chapter 10 Rotational Kinematics and Energy

3 Units of Chapter 10 Angular Position, Velocity, and Acceleration Rotational Kinematics Connections Between Linear and Rotational Quantities Rolling Motion Rotational Kinetic Energy and the Moment of Inertia Conservation of Energy

4 10-1 Angular Position, Velocity, and Acceleration

5 10-1 Angular Position, Velocity, and Acceleration Degrees and revolutions:

6 10-1 Angular Position, Velocity, and Acceleration Arc length s, measured in radians:

7 10-1 Angular Position, Velocity, and Acceleration

8 10-1 Angular Position, Velocity, and Acceleration

9 10-1 Angular Position, Velocity, and Acceleration

10 10-1 Angular Position, Velocity, and Acceleration

11 10-2 Rotational Kinematics If the angular acceleration is constant:

12 10-2 Rotational Kinematics Analogies between linear and rotational kinematics:

13 10-3 Connections Between Linear and Rotational Quantities

14 10-3 Connections Between Linear and Rotational Quantities

15 10-3 Connections Between Linear and Rotational Quantities

16 10-3 Connections Between Linear and Rotational Quantities This merry-go-round has both tangential and centripetal acceleration.

17 10-4 Rolling Motion If a round object rolls without slipping, there is a fixed relationship between the translational and rotational speeds:

18 10-4 Rolling Motion We may also consider rolling motion to be a combination of pure rotational and pure translational motion:

19 10-5 Rotational Kinetic Energy and the Moment of Inertia For this mass,

20 10-5 Rotational Kinetic Energy and the Moment of Inertia We can also write the kinetic energy as Where I, the moment of inertia, is given by

21 10-5 Rotational Kinetic Energy and the Moment of Inertia Moments of inertia of various regular objects can be calculated:

22 10-6 Conservation of Energy The total kinetic energy of a rolling object is the sum of its linear and rotational kinetic energies: The second equation makes it clear that the kinetic energy of a rolling object is a multiple of the kinetic energy of translation.

23 10-6 Conservation of Energy If these two objects, of the same mass and radius, are released simultaneously, the disk will reach the bottom first more of its gravitational potential energy becomes translational kinetic energy, and less rotational.

24 Summary of Chapter 10 Describing rotational motion requires analogs to position, velocity, and acceleration Average and instantaneous angular velocity: Average and instantaneous angular acceleration:

25 Summary of Chapter 10 Period: Counterclockwise rotations are positive, clockwise negative Linear and angular quantities:

26 Summary of Chapter 10 Linear and angular equations of motion: Tangential speed: Centripetal acceleration: Tangential acceleration:

27 Rolling motion: Summary of Chapter 10 Kinetic energy of rotation: Moment of inertia: Kinetic energy of an object rolling without slipping: When solving problems involving conservation of energy, both the rotational and linear kinetic energy must be taken into account.