What height (displacement) will a ball reach if thrown upward with an initial velocity of 15 m/s

11.48 m

Explanation:

initial velocity (u) = 15 m/s

acceleration due to gravity (g) = 9.8 m/s

final velocity (v) = 0 ( the ball's speed reduces gradually when thrown until    

                                   becomes 0 at maximum height)

find the height reached.

          we cannot apply this formula directly because we do no know the time        

          (t), so we first need to find the time

       0 = 15 + (-9.8 x t)   (the negative sign is because the ball is decelerating

         upwards)

         15 = 9.8t

         t = 1.53 s

       height (s) = (15 x 1.53)  + (0.5 x (-9.8) x 1.53^{2})

       height = 22.95 - 11.47 = 11.48 m

the average speed is 24.57 km/hr