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:

(0.1) 
But, so

(0.2) 
The first equation is easily solved:

(0.3) 
and so

(0.4) 
where a and b are constants to be determined. Since and , it is easy to show that . Therefore

(0.5) 
Since ,

(0.6) 
Finally, from the equation (0.2) for F,
. 
(0.7) 
Early trajectory of m for R_{0}=1
Trajectory of m for R_{0}=1 over 360^{0} (note log scale for r)