A ball is projected vertically upwards from point A A\,A with speed 14 m s-1. Point B B\,B is 6 m vertically above AAA. Model the ball as a particle moving freely under gravity and use g=9.8 m s−2g=9.8\text{ m s}^{-2}g=9.8 m s−2.
Show that the ball passes through B B\,B twice.
Find the two times after projection at which the ball passes through BBB.