A particle is projected from the ground with speed u at angle 60° from horizontal. It collides with a second particle of same mass moving with horizontal speed u in same direction at highest point of its trajectory. If collision is perfectly inelastic then find horizontal distance travelled by them after collision when they reached at ground
(1) 3√6u2/8g
(2) 3√3u2/8g
(3) u2/8g
(4) √3u2/g