Projectile Mania

2 balls of equal mass $2 \text { kg}$ are kept on flat ground at a distance $D$ from each other. They are thrown towards each other at an angle $\theta$ with a speed $v$ . They collide in mid-air elastically. Find the distance between them when they first come back to ground after collision.

Details and Assumptions :

• $D = 80 \text{ m}$ , $\theta = 37^\circ$ , $v = 50 \text{ m/s}$ , $g = 10 \text{ m/s}^{2}$ .