Motion along a straight lineAQA A-Level Physics: Subtopic test

1. 1
   A cyclist starts from rest and accelerates uniformly at 1.2 m s⁻² along a straight, level road for 10 s.

   (a)

   What is the cyclist's velocity at the end of the 10 s?

   [1 mark]

   • A0.12 m s⁻¹
   • B6.0 m s⁻¹
   • C8.3 m s⁻¹
   • D12 m s⁻¹

   (b)

   What distance does the cyclist travel in the 10 s?

   [1 mark]

   • A60 m
   • B120 m
   • C12 m
   • D6.0 m

   (c)

   The cyclist then brakes uniformly and stops in 4.0 s. Calculate the distance travelled while braking.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A small ball is released from rest above a hard floor and falls freely, hitting the floor 0.60 s later. It rebounds vertically with a speed of 4.4 m s⁻¹. Ignore air resistance and take g = 9.81 m s⁻².

   (a)

   Upward is taken as positive. What is the gradient of the velocity–time graph for the ball while it is in the air?

   [1 mark]

   • AZero throughout
   • B+9.81 m s⁻² throughout
   • C−9.81 m s⁻² throughout
   • DIts magnitude increases steadily

   (b)

   What was the height from which the ball was released?

   [1 mark]

   • A5.9 m
   • B3.5 m
   • C2.9 m
   • D1.8 m

   (c)

   Calculate the maximum height reached by the ball after the first bounce.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A student determines the acceleration of free fall, g, by dropping a steel ball from rest from different heights h above a trapdoor. An electromagnet holds the ball and an electronic timer starts when the ball is released and stops when the ball hits the trapdoor. She measures the fall time t for each height and plots a graph of t² against h.

   (a)

   Explain why this graph should be a straight line through the origin, and state what its gradient equals.

   [3 marks]

   (b)

   The line of best fit has a gradient of 0.205 s² m⁻¹ and cuts the t² axis at a small positive value instead of passing through the origin. Calculate g from the gradient, identify a systematic error that could cause the positive intercept, and state one way to reduce the effect of random errors in the timings.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A train starts from rest and accelerates uniformly at 0.80 m s⁻² for 25 s along a straight track. It then travels at constant speed for 60 s and finally brakes uniformly to rest in 20 s.

   (a)

   Calculate the total distance travelled by the train and its average speed for the whole journey.

   [6 marks]

   (b)

   Describe how the three stages of the journey would appear on a velocity–time graph and on a displacement–time graph, and explain how the acceleration and the total displacement can be found from the velocity–time graph.

   [6 marks]

   Total for question 4: 12 marks

End of questions