Graphs 3
2 marks · NormalThe distance–time graphs of two runners, Helen and Marco, show Helen's graph as a straight line and Marco's as a curve starting steeper and becoming less steep.
What can you say about the speed of each runner during their run? Explain your answer.
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
Helen runs at constant speed; Marco starts fast and slows down.
Also accept: Helen's speed is constant; Marco's speed decreases; Helen moves with steady speed, Marco decelerates
Common mistakes: Mixing up which runner has constant speed or variable speed.
Show mark scheme and worked solution
Marking points
B1 · 1 mark · States that Helen runs at constant speed.
B1 · 1 mark · States that Marco starts fast and then slows down.
Worked solution
Helen's graph is a straight line so speed is constant. Marco's graph gets less steep, so the gradient decreases, meaning he slows down during his run.