l. a) A boy throws a ball vertically upwards from the top of a tower which is 12m high. If the ball passes him again 0.75s later, assuming the value of g = 9.81mS'2, compute i. the velocity at which it was thrown [5 marks] ii. total time of ight [5 marks] iii. the velocity at which the ball will strike the ground (foot of the tower) [5 marks]