Graphs 3
4 marks · HardBelow is an extract from a distance–time graph that describes part of Rob's run:
Describe what Rob does between each of these time intervals: (a) 0–6 min, (b) 13–18 min, (c) 18–25 min, and (d) 25–30 min.
0–6 min:
13–18 min:
18–25 min:
25–30 min:
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) Rob moves away from home at a steady speed.
(b) Rob continues to move away from home but at a slower speed.
(c) Rob is stationary (he has stopped moving, distance does not change).
(d) Rob moves towards home (distance is decreasing).
Common mistakes: Confusing stationary segments with no movement; Misreading the direction of movement (return vs. away)
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Identifies Rob moves away from home at a steady speed.
B1 (b) · 1 mark · Identifies movement away from home but at a slower speed.
B1 (c) · 1 mark · Identifies Rob is stationary.
B1 (d) · 1 mark · Identifies Rob is moving towards home.
Worked solution
a) 0–6 min: The graph is a straight line sloping upward, so Rob is moving away from home at a steady speed.
b) 13–18 min: The graph is still increasing but less steep, so Rob continues moving away from home, but more slowly.
c) 18–25 min: The graph is horizontal; Rob is stationary (the distance does not change).
d) 25–30 min: The graph slopes downwards; Rob is moving towards home.