At t=0 the angular velocity of the mass is  and the string breaks.  For later times a force acts which keeps the angular velocity  constant at .  The force has no radial component, i.e., .  Find .


First, write Newton’s second law:


 But,  so


The first equation is easily solved:


and so



where a and b are constants to be determined.  Since  and , it is easy to show that .  Therefore


Since ,


Finally, from the equation (0.2) for F,






Early trajectory of m for R0=1



Trajectory of m for R0=1 over 3600 (note log scale for r)