EXAM 1                  October 2, 1991            PS 207                      
                                                                               
      If you need a constant not given here or do not understand a             
problem, please ask me about it.  Remember to include diagrams and             
explain your reasoning.  No notes, books, etc. may be used during this         
exam.                                                                          
              2            2                                                   
 g = 9.8 m/sec  = 32 ft/sec                                                    
                                      -31                                      
 The mass of the electron is 9.11 x 10    kg                                   
                                                                               
                                                                               
      1. (10 points).  State and explain how to remember (not                  
necessarily derive)                                                            
                                                                               
         (a).  The relation for the position of a particle as a                
function of time for motion in one dimension with constant                     
acceleration.                                                                  
                                                                               
         (b).  The relation giving the magnitude of the centripetal            
acceleration for a particle moving at constant speed v  in a circle of         
radius  R.                                                                     
                                                                               
                                                                               
                                                                               
 The remaining problems count 30 points each.  A diagram is required           
for each problem.                                                              
                                                                               
                                                                               
                                                                               
      2.  What is the average magnitude of the centripetal acceleration        
of a race car which wins a race of  N  laps  with a winning time of  T         
hours racing  around a circular racetrack of radius  R  miles?                 
                                                                               
                                                                               
      3.  (From homework, with inessential editting for aesthetics)            
                                  o                                            
 A plane, diving at an angle of 53  with the vertical, releases a bale         
of hay at an altitude of 730 m.  The bale hits the ground 5.0 s after          
being released.                                                                
                                                                               
         (a).  What is the speed of the plane?                                 
                                                                               
         (b).  How far did the bale travel horizontally during its             
flight?                                                                        
                                                                               
      4.  Just as a car starts to accelerate from rest with                    
                    2                                                          
acceleration 1.4 m/s  , a bus moving with constant speed of 12 m/s             
                                                                               
passes it in a parallel lane.                                                  
                                                                               
         (a).  How long will it be before the car overtakes the bus?           
                                                                               
         (b).  How fast will the car then be going?