Question

the graph shows the motion of a student. which of the statements best describes the movements of the student?
the student started at position 1m and walked forwards for 2s, stopped and then walked forward for 2 more seconds
the student started at position 0m and walked forward for 2s and then walked backwards faster, for 2s
the student started at position 1m and walked forward and the at 2s started walking forward faster
the student started at position 1m and walked forward for 2s then walked backwards faster, for 2s

Explanation:

Step1: Analyze starting - point

At time \(t = 0\ s\), the position is \(x=1\ m\). So the student starts at position \(1\ m\).

Step2: Analyze first - stage motion

From \(t = 0\ s\) to \(t = 2\ s\), the position decreases. The student is walking backwards.

Step3: Analyze second - stage motion

From \(t = 2\ s\) to \(t = 4\ s\), the position increases. The slope of the position - time graph from \(t = 2\ s\) to \(t = 4\ s\) is steeper than the slope from \(t = 0\ s\) to \(t = 2\ s\). Steeper slope means higher speed. So the student walked forward faster from \(t = 2\ s\) to \(t = 4\ s\).

Answer:

The student started at position 1m and walked backwards and then at 2s started walking forward faster.