Intelligent assessment and revision tools for OCR A Physics

In a lab tracking experiment, the displacement s of a trolley along a straight track is plotted against time t. The graph has three sections: 0–3 s: s increases linearly from 0 m to +6 m; 3–5 s: s remains constant at +6 m; 5–9 s: s decreases smoothly from +6 m to –2 m and the curve gets progressively steeper as time increases. Which statement must be true?

• A The trolley’s average velocity over 0–9 s is zero because it finishes near where it started.
• B Between 5 s and 9 s the trolley is moving toward its starting point and speeding up.
• C The total distance travelled from 0 to 9 s is 8 m.
• D During 3–5 s the trolley’s speed is negative because the graph is flat.