A ) The displacement: d = v o t - (gt²) / 2 = = 19.6 m/s × 1 s - ( 9.8 m/s² x 1 s² ) / 2 = = 19.6 m - 4.9 m = 14.7 m b ) v = v o - g t 0 = 19.6 m/s - 9.8 t ( when the ball is at the highest point ) 9.8 t = 19.6 t = 19.6 : 9.8 t = 2 s h = v o t - (gt²)/2 = 19.6 x 2 - ( 9.8 x 4 ) / 2 = 39.2 - 19.6 h = 19.6 m c ) h = gt² / 2 19.6 = 9.8 t²/2 9.8 t² = 39.2 t² = 39.2 : 9.8 t² = 4 t 2 = 2 s ( and we know that t 1 = 2 s ) t = t 1 + t 2 = 2 s + 2 s = 4 s
