1. A slow-motion camera is used to record the motion of a cricket ball projected directly upwards from ground level.  The motion of the cricket ball is modelled by the function

$h(t)=15t-4.9{t}^{2}t>0$

where $h$ metres is the height of the cricket ball above ground level after $t$ seconds.
The camera will capture the cricket balls’ motion whilst it is between heights of 2 m and 4 m above the ground.

Find the maximum height the cricket ball reaches and how long it takes to reach this point.