Year 9 Science · Unit 4 · Lesson 14
Challenge Worksheet
Learning Goals
Reading a speed-time graph
Study the speed-time graph below showing a 4-segment journey. Answer the questions that follow.
1. Calculate the acceleration during Segment 1 (0 to 5 s). Use a = (v − u) ÷ t. Show your working.
2. Calculate the distance travelled during Segment 2 (5 to 15 s). Hint: area of a rectangle = base × height.
3. Compare Segment 3 to Segment 1. Both involve a speed change of 20 m/s, but in different times. Which segment has greater acceleration magnitude? Explain what this looks like on the graph.
Evaluate a manufacturer's claim
A car manufacturer claims their sports car can accelerate from 0 to 100 km/h in 4.2 seconds. A standard family car takes 9.5 seconds to reach the same speed. Note: 100 km/h = 27.8 m/s.
(a) Calculate the acceleration of the sports car in m/s². Show your working using a = (v − u) ÷ t.
(b) Calculate the distance covered by the sports car during this 4.2-second acceleration. Use: distance = area under v-t graph = ½ × base × height (triangle for uniform acceleration from rest). Show your working.
(c) Calculate the acceleration of the standard family car, then calculate how many times greater the sports car's acceleration is. Comment on what this difference means for the driver's experience.
Wrap Up
In one sentence, what was the main idea of this lesson?