A train enters a level straight stretch of track with a speed of 20ms−1. It slows down uniformly at 0.5ms−2 until its speed becomes 10ms−1, after which it immediately accelerates uniformly at 0.8ms−2 until its speed reaches 25ms−1.
a. (i) Calculate the time taken in each phase of motion.
b. (ii) Find the total distance covered during the entire process.