The distances and times for a school bus travelling from the hostel to the museum are given below:
Stage 1: 750m in 3min
Stage 2: 4km in 7min
Stage 3: 9km in 12min
Rest: 5min at the bus depot
Stage 4: 15km in 20min
(i) Calculate the total distance covered and the total time taken, including the rest period.
(ii) Determine the bus’s average speed for the journey from the hostel to the museum, expressing your answer in km h−1.
(iii) If the bus returns directly from the museum to the hostel along the same road in 30min without any stop, calculate the magnitude of its average velocity for the complete round trip starting and ending at the hostel.
(iv) Comment briefly on how the inclusion of the 5min rest period affects the value obtained in part (ii).