Ok, so we're given an initial velocity of 10ms^-1 and an angle of 60 to the horizontal
So initial horizontal component of velocity is 5ms^-1 (ie 10cos60) and initial vertical is 10sin60 (around 8.66)
At max height, vertical velocity is 0,
so 0 = 10sin60 - 9.8t
t = 10sin60/9.8
This is half the...