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4024/11 Oct/Nov 2020, Question 23: Speed-Time Graphs and Acceleration

Cambridge O Level Mathematics 4024 · Paper 11 (Non-calculator) · Non-calculator · 5 marks

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The question, in short

Using a speed–time graph where speed is 20 m/s for 40 s then falls uniformly to 0 at 100 s, find deceleration, a time, and average speed.

Summarised in our own words. Use the official paper for the exact wording and any diagrams.

Part (a) · 1 mark

Find the deceleration of the train between t = 40 and t = 100.

  1. 1Deceleration = 20 ÷ 60
  2. 2= 1/3 m/s²

Answer1/3

Part (b) · 1 mark

Find the time t at which the train's speed is 10 m/s.

  1. 1Speed falls by 1/3 m/s each second; 10 m/s drop takes 10 ÷ 1/3 = 30 s
  2. 2t = 40 + 30 = 70

Answer70

Part (c) · 3 marks

Find the average speed of the train over the whole 100 seconds.

  1. 1Distance = area = 1/2 × 20 × (40 + 100) = 1400 m
  2. 2Average speed = 1400 ÷ 100 = 14 m/s

Answer14

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Also searched as: 4024/11/O/N/20 · 4024_w20_qp_11 · 4024 w20 11 · question 23.
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