PHYS 1111 - Introductory Physics I
Chapter 10 - Rotational Kineatics and Energy

Study Assignment:

Chapter 10, Sections 10.1 - 10.6, 6.5

Lesson notes:

In this chapter we will begin our study of rotational motion. We will define the fundamental kinematic quantities associated with rotational motion and examine the relationships between angular and linear quantities. Many new symbols will appear in this chapter; however, you should be able to use analogies with the translational kinematics studied at the beginning of the course to recognize that the relationships presented for rotational kinematics are of the same form. We will also introduce centripetal acceleration. It is very important that you understand that this acceleration is due to the external forces acting on an object. The term, centripetal force, often leads to confusion in this regard. The centripetal force is simply the mass of the object multiplied by the object's centripetal acceleration. The centripetal force is not a new type of force; it does not appear on a free body diagram. A new quantity, moment of inertia, will be introduced. Just as mass is the quantity responsible for resistance to change in velocity, moment of inertia is the quantity responsible for resistance to change in angular velocity. From this chapter we will also learn how to calculate the kinetic energy of a rotating body and apply conservation of mechanical energy to the motion of rolling bodies.

Objectives:

1. Understand the definitions of angular displacement, angular velocity and angular acceleration.

2. Be able to interpret and apply the rotational kinematic equations to the rotation of rigid bodies moving with constant angular acceleration about a fixed axis of rotation.

3. Be able to relate angular and linear variables for circular motion.

4. Be able to calculate the magnitude of the centripetal acceleration of a particle given its speed.

5. Be able to apply Newton's 2nd Law to analyze the motion of a body undergoing uniform circular motion in problems.

6. Be able to explain the difference between real forces and fictitious forces in a rotating system.

7. Be able to determine the moment of inertia of a system of particles with respect to an arbitrary axis of rotation.

8. Be able to determine the kinetic energy of rotating rigid body.

9. Be able to determine the kinetic energy of a rolling body.

10. Be able to apply the law of conservation of mechanical energy to rolling body problems.

 

Vocabulary:

rigid body
angular position and displacement
instantaneous angular velocity and instantaneous angular acceleration
centripetal
uniform circular motion

axis of rotation
moment of inertia
rotational kinetic energy

 

Homework:

See the homework solutions page here.

Last update: January 07, 2011