EXAM 1                  October 5, 1988            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
                  g = 9.8 m/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.


2.  (30 points).  An automobile travels at a steady 93 km/hr
along a road leading over a small hill.  The top of the hill is
rounded so that, in the vertical plane, the road approximately
follows an arc of a circle of radius 70 m.

     (a).  What is the centripetal acceleration of the
automobile at the top of the hill?



     (b).  Will it actually remain in contact with the
ground?



3.  (From homework, converted to algebra; 30 points).  A balloon

is ascending at a speed of  v   at a height  h  above the ground 
                             0                          
when a package is dropped.  How long does it take the package to

reach the ground?



4.  (30 points).  Projectile  A  is shot with a speed of
                         o               
150 m/s at an angle of 53  above the horizontal.  Simultaneously a

second projectile is shot straight up from some point  x   which
                                                        B
lies below  A's  line of flight.


(a).  If the two projectiles are to collide, how fast

must the second projectile be shot?  Give both an algebraic and a

numerical answer.

(b).  What value or values are permissable for  x  ?
                                                 B      
[Either an algebraic or numerical expression will do here.]