Motion graphsIB MYP Physics: Subtopic test

1. 1
   A cyclist in Amsterdam rides along a straight cycle path. Her speed increases uniformly from 0 to 8 m/s in 4 s. She then rides at a constant 8 m/s for 10 s, before slowing down uniformly to rest in 6 s. A student draws a speed-time graph of her ride.

   (a)

   What does the speed-time graph look like during the first 4 s?

   [1 mark]

   • AA straight line sloping upwards
   • BA horizontal line
   • CA straight line sloping downwards
   • DA curve that gets steeper and steeper

   (b)

   What is the cyclist's acceleration during the first 4 s?

   [1 mark]

   • A32 m/s²
   • B2 m/s²
   • C0.5 m/s²
   • D12 m/s²

   (c)

   State what the graph shows about her motion between 4 s and 14 s and explain how you can tell.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A student in Doha walks along a straight road. She walks 120 m away from home in 80 s at a steady speed. She then stops at a friend's house for 40 s. She then walks a further 180 m in 90 s at a steady speed. A distance-time graph is drawn of her walk.

   (a)

   What does the flat section of the distance-time graph show?

   [1 mark]

   • AShe walks at a constant speed
   • BShe walks faster
   • CShe is at rest
   • DShe walks back towards home

   (b)

   What is her speed in the last part of the walk?

   [1 mark]

   • A0.5 m/s
   • B1.5 m/s
   • C90 m/s
   • D2.0 m/s

   (c)

   Calculate her speed in the first part of the walk and use it to explain which of the two walking sections of the graph is steeper.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A lorry sets off from rest on a straight, flat road in Nairobi. Its speed increases uniformly to 12 m/s in 6 s, and then stays constant at 12 m/s for a further 20 s. A speed-time graph is drawn of the lorry's journey.

   (a)

   Calculate the distance the lorry travels in the first 6 s.

   [3 marks]

   (b)

   Calculate the total distance the lorry travels in the 26 s and its average speed for the journey.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A sports academy in Johannesburg gives its athletes GPS tracking vests during training. The vests record each athlete's speed every second, and coaches use the data to draw speed-time graphs. One sprinter's training run was: speed increases uniformly from rest to 10 m/s in 4.0 s, stays constant at 10 m/s for 6.0 s, then decreases uniformly to rest in 5.0 s.

   (a)

   Use the data to calculate the sprinter's acceleration in the first 4.0 s, the total distance she runs and her average speed for the whole 15 s run.

   [6 marks]

   (b)

   The academy is thinking of making all of its athletes wear the GPS vests in every training session. Discuss and evaluate whether it should do this.

   [6 marks]

   Total for question 4: 12 marks

End of questions