6.2 Area Under A graph
面积 距离
问题要求找的 distance
就像上一堂课学的 area
Distance travelled A - triangle
B - rectangle
B = 1 2 60 4 60 1 2 60 C - triangle
AC 2 2
= 360 km
Distance travelled A - trapezium
B - rectangle
= 1 (10 20) 5 5 20 1 10 20 C - triangle
AB C 2 2
= 275 m
AB C
(a) 1 (20 40) 8 10 40 1 12 40 880
2 2
Total distance (30 minutes) = 880 14 2 km
60 3
(b) Average speed = 14 2 1 Total distance = 14 2 km
32 3
29 1 kmh1 Total time = 30 minutes = 1 hour
3 2
distance
(a) 1 (t 6) 8 1 (8 12) 6 100 Time = t – (t – 6)
2 2 = t–t+6
4t 24 60 100
4t 36 100 =6
4t 100 36
t 64
4
t 16
100
(b) Average speed =
16
6.25 ms1
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(a) 180 km (b) 7.5 km
(a) 55 km
(b) 80 km
(c) 155 km
88 m