On the Physical Properties of Spherically Symmetric Self-Similar   Solutions
  In this paper, we are exploring some of the properties of the self-similar solutions of the first kind. In particular, we shall discuss the kinematic properties and also check the singularities of these solutions. We discuss these properties both in co-moving and also in non co-moving (only in the radial direction) coordinates. Some interesting features of these solutions turn up. 
M. Sharif and Sehar Aziz