CHAPTER 5CIRCULAR MOTION AND

GRAVITATION

Kinetics of Uniform Circular Motion

• An object moving in circular motion is in constant acceleration, even if it maintains its speed…it is changing direction…thus changing velocity!

• Centripetal or radial acceleration points towards the center of revolution. (ar )

• ar = v2 / r where v is tangential velocity.

Frequency and Period

• Frequency and period are inversely related.

• 1/f = T

• vt = 2pr/T

• See Example 5-1

Dynamics of Uniform Circular Motion

• Since centripetal acceleration points towards the center, the force causing the acceleration must also be pointed to the center.

• The term “centripetal force” is not a new force, but it is sometimes used to refer to the force causing centripetal acceleration.

• See examples 5-3 and 5-4

Homework

•Page 138questions 1-4•Page 138 problems 1-4