A ball is projected vertically upwards from point O O\,O with speed 12 m s-1. Point A A\,A is 5 m vertically above OOO. The ground is 8 m vertically below OOO. 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.
Determine the two times at which the ball passes AAA.
Determine the time at which the ball reaches the ground.
Find the speed with which the ball reaches the ground.