<image>On Labor Day, Mingming's family and Yunyun's family set off in their respective cars. Please answer the following questions based on the diagram. (Mingming's car is Car A, Yunyun's car is Car B)

(1) Are the distances traveled by the cars proportional to time? If so, what is the proportion? Why? _
(2) What is the speed difference between Car A and Car B? _
(3) After 2.5 hours, how far apart are the two cars? _