Two students, Priya and Sameer, are asked to draw the speed–time graph for a toy train that moves at constant speed around a circular track. Their drawings are described below:
• Graph P (Priya): a straight horizontal line at 4m/s from t=0 to t=30s.
• Graph Q (Sameer): a straight line that starts at 2m/s at t=0 and reaches 6m/s at t=30s.
Answer the questions that follow.
(i) Identify which graph correctly represents the speed–time relationship for the toy train. Give a reason for your choice.
(ii) Point out the conceptual error in the incorrect graph.
(iii) If the length of the circular track is 31.4m, determine how many complete revolutions the toy train makes in 30s using the correct graph.