Ch.1 Distance ( 距離 ) & Displacement ( 位移 ) 1 Tai Wai Station Kowloon Tong Station displacement 4 km to the north distance 4.4 km

2 Class Exercise 1.1 Distance travelled = ?

3 Class Exercise 1.1 Distance travelled = = 180 m

4 Displacement ( 位移 ) = change in position The change in position is a straight line joining the start position ( 起點 ) and the end position ( 終點 ). Magnitude ( 量值 ) : Length of the straight line joining the start position and the end position. Direction ( 方向 ) : Direction of the straight line from the start position to the end position.

5 North ( 北 ) West ( 西 ) East ( 東 ) South ( 南 )

6 N 40° Direction = ?

7 N 40° Direction = 50° 50 ° E

8 N 60° Direction = ?

9 N 60° Direction = 150° S E 90° + 60° = 150°

10 N 40° Direction = ?

11 N 40° Direction = 230 ° S W 50° 90° + 90° + 50° = 230 °

12 N 40° Direction = ?

13 N 40° Direction = 320° W 270° + 50° = 320°

14 Class Exercise 1.2 Magnitude of displacement = ? Direction of displacement = ?

15 Class Exercise 1.2 Magnitude of displacement = 128 m Direction of displacement = 180º + 40° = 220°

16 Class Exercise 1.3 (a) & (b)

17 Class Exercise 1.3 (a) & (b) 6 m East (90°) 6 m East

18 Class Exercise 1.3 (c) & (d)

19 Class Exercise 1.3 (c) & (d) 6 m East

20 Note: If the starting position and the end position are the same, the displacement is the same.

21 Class Exercise 1.4 (a) You walk from LPSMC to the Entrance C of the Tsuen Wan MTR station. Find the magnitude and direction of your displacement.

22 Class Exercise 1.4 (a) 6.2 cm 3.2 cm Magnitude = ? Direction = ?

23 Class Exercise 1.4 (a) 6.2 cm 3.2 cm Magnitude = (6.2 ÷ 3.2 ) × 100 = 194 m Direction = 180° + 77° = 257° (S 77 W) 78°

24 Class Exercise 1.4 (b) You meet your friend, Tommy, at Entrance C. He is going to the YMCA in Luk Yeung Sun Chuen. What is his displacement from Entrance C to the YMCA?

25 Class Exercise 1.4 (b) 3.2 cm Magnitude = ? Direction = ? 3.7 cm

26 Class Exercise 1.4 (b) 3.2 cm Magnitude = (3.7 ÷ 3.2 ) × 100 = 116 m Direction = 50° (N 50 E) 3.7 cm 50°

27 Class Exercise 1.5 Mr. Chan walks 3 m from A to the East. He turns 90  and walks 6 m to the South. Finally he walks a further distance of 9 m to the West. (a) In the space below, draw arrows to represent these displacements. (Use 1 cm to represent 1 m.)

28 Class Exercise 1.5 (a)

29 Class Exercise 1.5 (a)

30 Class Exercise 1.5 (b) (b) direction and magnitude of the total displacement = ?

31 Class Exercise 1.5 (b) magnitude of the total displacement = 8.5 m direction of the total displacement = 180° + 45° = 225° 45°

32 Class Exercise 1.6 (a)

33 Class Exercise 1.6 (a) 12 m East

34 Class Exercise 1.6 (a) 12 m 6 m East

35 Class Exercise 1.6 (a) 12 m 6 m 18 m East

36 Class Exercise 1.6 (b)

37 Class Exercise 1.6 (b) S

38 Class Exercise 1.6 (b) -10 m or 10 m (West) S

39 Class Exercise 1.6 (b) -10 m or 10 m (West) 8 m (East) S

40 Class Exercise 1.6 (b) -10 m or 10 m (West) 8 m (East) 28 m S

41 Class Exercise 1.7

42 Class Exercise 1.7 distance = = 7 m

43 Class Exercise 1.7

44 Class Exercise ° magnitude = direction = 90 ° + 37° = 127° (S 53 E) m

45 Class Exercise °

46 Class Exercise ° P

47 Class Exercise m or 4.0 m (West) 3.0 m (South) 62° P

48 Scalar ( 無向量 )Vector ( 向量 / 矢量 ) has magnitude ( 量值 ) only. has both magnitude and direction. Example: distance ( 距離 ) time ( 時間 ) temperature ( 溫度 ) speed ( 速率 ) …… Example: displacement ( 位移 ) velocity ( 速度 ) acceleration ( 加速度 ) force ( 力 ) …… 1.3 Scalar and Vector

49 Homework: Assignment Book 1. Chapter 1: Distance & Displacement Q.1 – Q.6 (p.1-5) 2. Deadline: ____