Summary
S S
You should know: ◆ about graphs of distance–time and speed–time ◆ the meaning of acceleration ◆ about vector and scalar quantities, speed and velocity ◆ that acceleration is a vector quantity.
End-of-chapter questions 1
A bus is travelling along a road. It travels a distance of 400 m in a time of 25 s. a Write the equation used to calculate the average speed of the bus. b What is the unit of average speed? The graph shows that the bus’s speed is constant.
Speed / m/s
20 15 10 5 0 0
5
10
15 Time / s
20
25
c Explain how you can tell that the bus has no acceleration. d Copy the graph and shade the area that represents the distance travelled by the bus. Label this area ‘distance travelled’. 2
Here are two graphs that represent the motion of two different objects.
Speed
Distance travelled
S
Time A
Time B
a Copy the distance–time graph. Use your graph to explain how you would find the object’s speed. b The object is moving with constant speed. Explain how you can tell this from the graph. c Copy the speed–time graph. Use your graph to explain how you would find the object’s acceleration.
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Cambridge IGCSE Physics
Original material © Cambridge University Press 2014