Summary

• Center of mass
• Rotation variables
• Rotational kinematics

• Reading Quiz



• Rolling motion
  • combine translation & rotation
    Example #1
    
  
  
  
  
  
  
• Energy in rotation
  • moment of inertia
  • rotational energy
    Example #2
    
  • rolling down an incline applet
  
  
• Conceptual Checkpoint 10-4
• Active Example 10-3




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Chapter 11

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• Torque
  • definition, units
  • vectors
    Example #3
    
  
  
  
  

Walker4e
Reading quiz A solid sphere and a hollow sphere of the same mass and radius roll without slipping at the same speed. The kinetic energy of the solid sphere is _____ the kinetic energy of the hollow sphere.
A. greater than
B. less than
C. the same as
Answer















gc6 8.21
The tires of a car make 65 revolutions as the car reduces its speed uniformly from 95 km/h to 45 km/h. The tires have a diameter of 0.80 m and they roll without slipping. What is the angular acceleration of the tires?
A. −0.661 rad/s²
B. −1.65 rad/s²
C. −4.13 rad/s²
D. −10.3 rad/s²
Answer







sb5 10.24
The CM of a 3.80 cm radius baseball moves at 38 m/s. The baseball spins with angular speed 125 rad/s. What is the ratio KE_CM/KE_rotation?
A. 160
B. 96
C. 4.21
D. 0.10
Answer















sj6 10.30
What torque does the fish exert about an axis perpendicular to the screen and passing through the fisherman's hand?
A. 168 N·m
B. 109 N·m
C. 200 N·m
D. 308 N·m

Answer















 



B. less than


The hollow sphere has a larger moment of inertia and therefore a larger rotational energy than the solid sphere. They each have the same translational kinetic energy. Therefore, the total kinetic energy of the solid sphere is less than the total kinetic energy of the hollow sphere.




















 



C. −4.13 rad/s²





















 



A. 160





















 



A. 168 N·m