Centripetual Force
Earnest S.Garrison                    Schurz H.S.
536 Landau                            794-8120
University Pk.Il. 60466
534-5146

Objectives:

             To illustrate the components that govern the size of
centripetal force in an object that moves in a circular path around
a central point.

Apparatus needed:
             
             Small glass tube (polished ends),2m of fishing line,
rubber stopper (#5),paper clips,10-1/4 of an inch washers,and a tim-
ing device with a second hand.

Recommended strategy:

             Attach one end of the fishing line to the rubber stopper
and pass the other end of the line through the glass tube. Then tie
the other end of the line to one of the paper clips.This device we
will call our centripetal force apparatus.It should look like the
following;


                                 STOPPER      ------->     ////////I
                                                         //        I
                                 _______________________I          I 
                               I I I                    I          I
                               I I I                      \\       I
                               I I I                        \\\\\\\I
                               I I I
                               I I I
                               I I I  <--------GLASS TUBE
                               I I I
                               I I I
                               I I I
                               I I I
                               I I I
                                 I
                                 I
                                 I
                                 I
                                 I
                                 I <--------FISHING LINE
                                 I
                                 I
                                 I
                             ____I____
                            I        I
                            I        I  <-----WASHERS
                            I        I
                            I________I

               The procedur to be used is to swing the stopper around
your head at a constant rate of speed and parallel to the floor.While
this happending others in the group count the number of revolution 
that the stopper makes in a 30 second period of time.This should be 
done using groups of washers as counter weights of 6,8,&10 each done 
for three trials.At the conclusion the group should be to plot a graph
of velocity square vs radius (of the circle that the stopper moved 
in).There should be some discussion concerning the effects of how 
as the number of washers & radius of rotation changed the effects on
the number of revolutions per second.