Describe the motion of the bus using a speed-time graph and calculate its average speed.

Hey General, good to see you again. Here's the solution for Item 3: a) Graphically understand the motion of the bus up to the point when it was brought to rest. Step 1: Analyze the motion of the bus in different phases. The motion of the bus can be divided into four phases: Phase 1 (0 to 60 s): The bus moves at a constant speed of 15 ms^-1 for 1 minute (60 s). Phase 2 (60 s to 90 s): The speed increases linearly from 15 ms^-1 to 25 ms^-1 over 30 s. Phase 3 (90 s to 270 s): The bus maintains a constant speed of 25 ms^-1 for 3 minutes (180 s). Phase 4 (270 s to 300 s): The bus decelerates linearly from 25 ms^-1 to 0 ms^-1 (rest) over 30 s. Step 2: Describe the speed-time graph. A speed-time graph for this motion would show: A horizontal line from (0, 15) to (60, 15), representing constant speed. A straight line sloping upwards from (60, 15) to (90, 25), representing constant acceleration. A horizontal line from (90, 25) to (270, 25), representing constant speed. A straight line sloping downwards from (270, 25) to (300, 0), representing constant deceleration. b) Estimate the average speed of the bus for the motion. Step 1: Calculate the distance traveled in each phase. Phase 1: d_1 = speed × time = 15 ms^-1 × 60 s = 900 m Phase 2: d_2 = (initial speed + final speed)2 × time = (15 ms^-1 + 25 ms^-1)2 × 30 s = 20 ms^-1 × 30 s = 600 m Phase 3: d_3 = speed × time = 25 ms^-1 × 180 s = 4500 m Phase 4: $d_4 = (initial speed + final speed)2 ×