A projectile is projected with a speed of 150 ms−1 making an angle 60° with the horizontal. Reaching the highest point A, it explodes into two equal parts. The parts separate with a relative velocity...

A projectile is projected with a speed of 150 ms⁻¹
making an angle 60° with the horizontal. Reaching the highest point A, it explodes into two equal parts. The parts separate with a relative velocity of vrel in the horizontal direction. What should be the value of so that one half returns back to the point?