Chapter 10: Dynamics Of Rotational Motion

Chapter 10 LectureChapter 10:Dynamics ofRotationalMotion 2016 Pearson Education, Inc.

Goals for Chapter 10 To study torque. To relate angular acceleration and torque. To examine rotational work and include time tostudy rotational power. To understand angular momentum. To examine the implications of angularmomentum conservation. To study how torques add a new variable toequilibrium. To see the vector nature of angular quantities. 2016 Pearson Education, Inc.

Definition of Torque – Figure 10.1 Torque ( ) is definedas the force appliedmultiplied by themoment arm. The moment arm isthe perpendiculardistance from thepoint of forceapplication to thepivot point. 2016 Pearson Education, Inc.

There Is a Sign Convention – Figure 10.3 A counterclockwiseforce is designated aspositive ( ). A clockwise force isdesignated asnegative ( ). 2016 Pearson Education, Inc.

A Plumbing Problem to Solve – Example10.1 Refer to the worked problem on pages 284 and285. 2016 Pearson Education, Inc.

Why Do Acrobats Carry Long Bars? Refer to the photo caption on the bottom of page287. 2016 Pearson Education, Inc.

Torques on a Rod – Conceptual Analysis10.1 Refer to the worked example on page 284. 2016 Pearson Education, Inc.

Rotating Cylinders – Conceptual Analysis10.2 Refer to the worked example on page 287. 2016 Pearson Education, Inc.

Unwinding a Winch (Again) – Example 10.2 Refer to the worked problem on page 288. 2016 Pearson Education, Inc.

The Yo-Yo Rotates on a Moving Axis –Figure 10.12 Refer to worked example on page 290. 2016 Pearson Education, Inc.

A Bowling Ball Rotates on a Moving Axis –Example 10.5 Refer to worked example on page 291. 2016 Pearson Education, Inc.

Work Can Be Done By a Constant Torque –Figure 10.14 Example 10.6 followsthe generic situationto the right. 2016 Pearson Education, Inc.

Angular Momentum – Figure 10.15 The diver changesrotational velocities bychanging body shape. The total angularmomentum is themoment of inertiamultiplied by theangular velocity. 2016 Pearson Education, Inc.

Nifty Sculpture – Figure 10.17 Follow Example 10.7 to find angular momentumand rotational energy. 2016 Pearson Education, Inc.

Angular Momentum Is Conserved –Figure 10.19 The first figure showsthe figure skater witha large moment ofinertia. In the second figure,she has made themoment much smallerby bringing her armsin. Since L is constant,must increase. 2016 Pearson Education, Inc.

The Professor as Figure Skater? –Figure 10.22 Example 10.9 onpage 299 refers toFigure 10.22. It seems that dangerto the instructor isproportional tointerest in any givendemonstration. 2016 Pearson Education, Inc.

A New Equilibrium Condition – Figure 10.24 Now, in addition toadd, we also must Refer to Problem Solving Strategy 10.3 2016 Pearson Education, Inc.

Balancing on a Teeter-Totter – Figure 10.26 The heavier child must sit closer to balance thetorque from the smaller child. Refer to Example 10.11 on page 303. 2016 Pearson Education, Inc.

The Firefighter on the Ladder – Figure 10.27 This problem is "classic" and appears in oneform or another on most standardized exams. Refer to worked example on page 304. 2016 Pearson Education, Inc.

Balanced Forces During Exercise –Figure 10.27 Once again, a "classic" problem which alwaysappears in some form on standardized exams. Refer to the worked example on page 305. 2016 Pearson Education, Inc.

Angular Quantities Are Vectors –Figure 10.29 The "right-hand rule"gives us a vector'sdirection. 2016 Pearson Education, Inc.

Gyroscopes Can Add Stability –Figure 10.31 The gyroscopicmotion adds stabilityto bicycles, footballs,bullets and more. 2016 Pearson Education, Inc.

A Laboratory Gyroscope – Figure 10.33 Refer to the worked example on page 309. 2016 Pearson Education, Inc.

Definition of Torque – Figure 10.1 Torque ( ) is defined as the force