Explanation:
From the normal equation of motion, v=u+at
But in this case, the ball is projected upwards. Therefore we have the final velocity V as 0(at maximum height). Then the acceleration a =g = -9.8m/s^2
v=u+at
0 = 6 + (-9.8)t
0 = 6 - 9.8t
9.8t = 6
t = 6/9.8=0.61s
