Ch. 9 Rotational Dynamics
         PHYS 131 Recitation
          FOC Questions:
            1, 6, 10 and 17.
          Problems:
            5, 10, 12, 13, 31 & 34.
                                               FOC 1
            Section 9.1 The Action of Forces and Torques on Rigid Objects 
            1.  The wheels on a moving bicycle have both translational (or linear) and rotational 
            motions. What is meant by the phrase “a rigid body, such as a bicycle wheel, is in 
            equilibrium”?      The body cannot have translational or rotational motion of any kind.  
                           (a)
                The body can have translational motion, but it cannot have rotational motion.     The 
            (b)                                                                               (c)
            body cannot have translational motion, but it can have rotational motion. (d) The body 
            can have translational and rotational motions, as long as its translational acceleration and 
            angular acceleration are zero.  
                                                        FOC 6
                   6. Five hockey pucks are sliding across frictionless ice. The drawing shows a top view of 
                   the pucks and the three forces that act on each one. As shown, the forces have different 
                   magnitudes (F, 2F, or 3F), and are applied at different points on the pucks. Only one of 
                   the five pucks can be in equilibrium. Which puck is it?  
                       1      2     3      4      5 
                   (a)   (b)    (c)    (d)   (e)
                    
                                                                                                         
                                               FOC 10
               Section 9.4 Newton’s Second Law for Rotational Motion About a Fixed Axis 
               10. The drawing shows three objects rotating about a vertical axis. The mass of each 
                   
               object is given in terms of m , and its perpendicular distance from the axis is specified in 
                                           0
               terms of r0. Rank the three objects according to their moments of inertia, largest to 
               smallest. 
                   A, B, C     A, C, B    B, A, C      B, C, A    C, A, B 
               (a)         (b)         (c)         (d)         (e)
                                                                        
                                                      Problem 10