A lift in a school building moves vertically upward from the ground floor to the third floor, 12m above, in 4s. It then remains stationary for 2s to allow students to enter and finally moves up a further 6m to the fifth floor in 3s.
(i) Calculate the average speed of the lift for the entire journey from the ground floor to the fifth floor.
(ii) State whether the motion of the lift is uniform or non-uniform. Justify your answer clearly.
(iii) Suggest one operational change that would make the motion of the lift uniform while it travels the same total vertical distance.