Lift problems

From a lift moving upwards with a uniform acceleration $a=\SI[per-mode=symbol]{2}{\meter\per\second\squared}$ , a man throws a ball vertically upwards with a velocity $v_0=\SI[per-mode=symbol]{12}{\meter\per\second}$ relative to the lift. The ball comes back to the man after the time $t$ . Find the value of $t$ .