Consider the collision depicted in figure to be between two billiard balls with equal masses ${\mathrm{m}}_1={\mathrm{m}}_2$ .  The first ball is called the cue while the second ball is called the target.  The billiard player wants to ‘sink’ the target ball in a corner pocket, which is at an angle ${\mathrm{\theta }}_2={37}^{\circ }$

Assume that the collision is elastic and that friction and rotational motion are not important, Obtain ${\mathrm{\theta }}_1.$