Summary

• Torque & Newton's Second Law
• Static equilibrium
• Angular momentum

• Class Quiz    Timer
  
  

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  Chapter 12

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• Reading Quiz



• Orbits
  • canoeing example
  • characteristics of orbits
  • orbit applet
  • the Moon's orbit
    Example #1
    
  
  
• Newton's Universal Law of Gravitation
  • derivation
  • all masses gravitationally attract
  • ULG applet
    Example #2
    
  • Cavendish experiment video
  
  
• Orbits & Kepler
  1. Orbits are ellipses applet
  2. Planets sweep equal areas/time applet
  3. T ² ∝ r³
  
  
  
  

sec. 8.5
A 4.0 m long rod is hinged at one end and initially held in the horizontal position. What is its angular acceleration upon release?
A. 3.68 rad/s²
B. 2.45 rad/s²
C. 6.75 rad/s²
D. 4.90 rad/s²
Answer















Walker4e
Reading quiz Which portion of the sphere of mass M exerts the greatest force on the small mass m?
A. portion A
B. either portion D or C
C. portion B
D. All portions exert the same force on m.
Answer















 
The acceleration of the moon towards earth is 0.00272 m/s². How far does the moon fall in one second?
A. 1.36 mm
B. 2.72 mm
C. 7.40 mm
D. 27.2 mm
Answer















 
Say you and the person next to you are each 70 kg and are sitting 0.50 m apart. What is the force of attraction between you and they?
A. 9.34×10⁻⁹ N
B. 1.87×10⁻⁸ N
C. 6.54×10⁻⁷ N
D. 1.31×10⁻⁶ N
Answer























 



A. 3.68 rad/s²





















 



A. portion A

The force increases when the distance r decreases, so the nearest portion of the mass M exerts the greatest force on m. The combined force from all portions acts as if all of the mass M were concentrated at its center.
























 



A. 1.36 mm





















 



D. 1.31×10⁻⁶ N