Displacement – time graphAmy leaves her house, walks up the road to her friend, Saki, then down the road to her other friend Kam. The graph shows her journey.

Calculate each of the following.(a) Her total distance travelled.(b) Her final displacement.(c) Her velocity for each stage.(d) Her average speed.(e) Her average velocity.

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(a) 30 + 50 = 80m(b) - 20m(c) 1.5 ms-1, -2 ms-1

(d) 80 45 = 1.78 ms-1

(e) -20 45 = -0.444 ms-

1

Displacement – time graphThe displacement – time graph shows the journey of a woman going to a corner shop and back.

Calculate each of the following.(a) Her total distance travelled.(b) Her final displacement.(c) Her velocity for each stage.(d) Her average speed.(e) Her average velocity.

(a) 60 + 60 = 120m(b) 0(c) 2 ms-1, -3 ms-1

(d) 120 70 = 1.71 ms-1

(e) 0 45 = 0 ms-1

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A cyclist starts from town A to town B, 60 km away. In the first hour, she travels 20 km. She then rests for 15 minutes before completing the second stage of 20 km at the same speed. She then has a second 15-minute rest period before completing her final stage at the same as the previous two.

The second cyclist starts from B to cycle to A. He leaves at the same time as the first cyclist leaves A and travel non-stop at 15 kmh-1.

Sketch Displacement – time graph representing both journeys and estimate at what time and where do the two cyclists pass each other?

Time = 1hour 51mins

Distance = 32.1 km from A