Motion graphsIB MYP Sciences: Subtopic test

1. 1
   A student plots a distance–time graph for a toy robot moving along a straight corridor. The line rises in a straight slope from 0 m at 0 s to 12 m at 8 s, stays horizontal until 14 s, and then rises in a straight slope to 24 m at 20 s.

   (a)

   What is the robot doing between 8 s and 14 s?

   [1 mark]

   • AMoving at a constant speed
   • BSpeeding up
   • CStationary
   • DSlowing down

   (b)

   What is the robot's speed during the first 8 s?

   [1 mark]

   • A0.67 m/s
   • B1.5 m/s
   • C20 m/s
   • D96 m/s

   (c)

   Calculate the robot's speed between 14 s and 20 s.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A tram in Istanbul leaves a stop. Its velocity–time graph is a straight line rising from 0 m/s at 0 s to 12 m/s at 6 s, then a horizontal line until 16 s, then a straight line falling to 0 m/s at 20 s.

   (a)

   What does the area under a velocity–time graph represent?

   [1 mark]

   • ADistance travelled
   • BAcceleration
   • CAverage speed
   • DTime taken

   (b)

   What is the tram's acceleration during the first 6 s?

   [1 mark]

   • A72 m/s²
   • B0.5 m/s²
   • C6.0 m/s²
   • D2.0 m/s²

   (c)

   Describe, with a calculation, the motion of the tram between 16 s and 20 s.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   Priya, a student in Cape Town, investigates how the angle of a runway affects the acceleration of a trolley released from rest. A data logger plots a velocity–time graph for each run. She uses the same trolley and the same runway each time. Every graph is a straight line starting at the origin. The velocity after 1.0 s is 1.6 m/s for a runway angle of 10°, 3.2 m/s for 20° and 4.7 m/s for 30°.

   (a)

   Identify the independent variable, the dependent variable and one variable that Priya must control.

   [3 marks]

   (b)

   Process the data: calculate the acceleration of the trolley for the 20° runway, describe the trend in the results, and suggest one improvement to the investigation, with a reason.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A driverless metro train in Dubai follows a programmed journey between two stations. It accelerates uniformly from rest for 20 s until it reaches 20 m/s, travels at a constant 20 m/s for 60 s, and then decelerates uniformly to rest in 25 s.

   (a)

   Discuss the social and economic implications of using driverless trains whose acceleration and speed are controlled by computer.

   [6 marks]

   (b)

   Calculate the train's acceleration and deceleration, and use the area under its velocity–time graph to find the total distance between the two stations.

   [6 marks]

   Total for question 4: 12 marks

End of questions