The document discusses distance-time graphs and calculating speed from the gradient. It defines gradient as the rate of change of the vertical axis quantity over the horizontal axis quantity. For distance-time graphs specifically, the gradient represents speed. It provides an example of a distance-time table and graph, then instructs on calculating speed for different periods using the graph and gradient formula. Students are assigned a worksheet to calculate speeds from a sample distance-time graph.

3. GRADIENT AND AREA UNDER A GRAPH

4. Distance-Time Graph How to draw a graph? Recall previous knowledge x axis represent time y axis represent distance Note : When a distance-time graph is drawn, the gradient of the graph gives the speed.

5. Example The following table shows the distance travelled and time taken by Amin to his office. Draw the distance-time graph made by Amin 15 10 5 Distance (km) 0.3 0.2 0.1 Time (hours)

6. The Gradient of a Distance-Time Graph What is gradient? - Is the change of the quantity on the vertical axis with respect to the change of the quantity on the horizontal axis

7. How to find gradient? Recall the formula of gradient : m = Example :………….. What is the general equation of straight line? The gradient of distance-time graph represent speed

8. Please do worksheet 1…Exercise 6.1 B and 6.1 C with your partner Exercise

10. How to find speed for a period of time from a distance-time graph Notes:

11. The distance-time graph shows the distance covered by a boy from the starting point to another point and back. Example:

12. a) Find the speed for the first 15 seconds. b) How long did he rest? c) Find the speed where the boy back to starting point. d) Find the average speed for the whole journey. From the graph,

13. a) Find the speed for the first 15 seconds. Answers: a) Speed for the first 15 seconds:

14. Answers: b) How long did he rest? Time taken = 30 s – 15 s = 15 seconds -He takes 15 seconds to rest

15. Answers: c) The speed where the boy back to the starting point: Negative sign indicates the direction of the journey is reversed

16. Answers: d)

17. Please do worksheet 1. Exercise 6.1 D Exercise

18. Answers for Worksheet 1 (6.1D) a) Speed from technician workshop to the house of the first customer:

19. b) Speed from 1 st customer house to the 2 nd customer house (BC):

20. c)

21. Please do worksheet 2 Exercise

22. Submit it after the end of the class

23. SUMMARY Gradient of a graph is the rate of change in the quantity on the vertical axis with respect to the change in the quantity on the horizontal axis. Gradient of the distance-time graph represents the speed.

24. Formula used:

25. homework (ex6.1(d) , no 3&4)

26. THE END