11 Materials
Exam-style questions
AQA Physics
1
A rubber cord is used to provide mechanical resistance when performing fitness
exercises. A scientist decided to test the properties of the cord to find out how
effective it was for this purpose. The graph of load against extension is shown in
Figure 1 for a 0.50 m length of the cord.
Figure 1
Curve A shows loading and curve B shows unloading of the cord.
a
State which feature of this graph confirms that the rubber cord is elastic.
(1 mark)
b Explaining your method, use the graph (curve A) to estimate the work done
in producing an extension of 0.30 m.
answer =
c
J
(3 marks)
The scientist compared this cord with a steel spring that reached the same
extension for the same maximum load without exceeding its limit of proportionality.
i On Figure 1, draw the load–extension line for this spring up to a load of
50 N and label it C.
(1 mark)
ii With reference to the spring, explain what is meant by the limit of
proportionality.
(1 mark)
From AQA Physics A PHYA2 Mechanics, Materials and Waves June 2010
(Question 5)
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1
11 Materials
Exam-style questions
AQA Physics
2
A student is asked to investigate Hooke’s law; they are provided with a clamp
stand, a steel spring, a mass hanger and some 100 g masses, a metre rule, and
a set square. They measure the unstretched length of the spring and then set
up the arrangement shown in Figure 2.
Figure 2
a
Describe how you would use this arrangement to investigate Hooke’s law.
State the measurements you would make and explain how you would use
the measurements to calculate the spring constant for the spring.
(4 marks)
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2
11 Materials
Exam-style questions
AQA Physics
b If the student continued to add 100 g masses to the spring shown in Figure 2,
the equipment would become unsafe. Explain why.
(2 marks)
3 A type of exercise device is used to provide resistive forces when a person
applies compressive forces to its handles. The stiff spring inside the device
compresses as shown in Figure 3a.
Figure 3a
a
The force exerted by the spring over a range of compressions was measured.
The results are plotted on the grid in Figure 3b.
Figure 3b
i
State Hooke’s law.
(2 marks)
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11 Materials
Exam-style questions
AQA Physics
ii
State which two features of the graph confirm that the spring obeys
Hooke’s law over the range of values tested.
(2 marks)
iii Use the graph to calculate the spring constant, stating an appropriate unit.
answer =
(3 marks)
1
F ΔL.
2
Explain how this formula can be derived from a graph of force against
extension.
b The formula for the energy stored by the spring is E =
(3 marks)
From AQA Physics A PHYA2 Mechanics, Materials and Waves January 2011
(Question 1)
© Oxford University Press 2015
www.oxfordsecondary.co.uk/acknowledgements
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4
11 Materials
Exam-style questions
AQA Physics
4 Two identical springs, each having a spring constant of 85 N m–1, are shown
arranged in parallel and series in Figure 4.
Figure 4
A load of 15 N is attached to each arrangement.
a
Calculate the extension for the parallel arrangement when the load is midway
between the lower ends of the springs.
answer =
m
(2 marks)
answer =
m
(2 marks)
b Calculate the extension for the series arrangement.
c
Calculate the energy stored in the parallel arrangement.
answer =
© Oxford University Press 2015
J
(2 marks)
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11 Materials
Exam-style questions
AQA Physics
d Without further calculation, discuss whether the energy stored in the series
arrangement is less, or greater, or the same as in the parallel arrangement.
(3 marks)
From AQA Physics A PHYA2 Mechanics, Materials and Waves June 2012
(Question 5)
© Oxford University Press 2015
www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original
6
11 Materials
Exam-style questions
AQA Physics
5 Figure 5 shows a stress–strain graph for a copper wire.
Figure 6
a
Define tensile strain.
(1 mark)
b State the breaking stress of this copper wire.
answer =
c
Pa
(1 mark)
Mark on Figure 5, a point on the line where you consider plastic deformation
may start.
Label this point A.
(1 mark)
d Use the graph to calculate the Young modulus of copper. State an
appropriate unit for your answer.
answer =
(3 marks)
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7
11 Materials
Exam-style questions
AQA Physics
e
The area under the line in a stress–strain graph represents the work done
per unit volume to stretch the wire.
i Use the graph to find the work done per unit volume in stretching the wire
to a strain of 3.0 × 10–3.
answer =
J m–3
(2 marks)
ii
Calculate the work done to stretch a 0.015 kg sample of this wire to a
strain of 3.0 × 10–3.
The density of copper = 8960 kg m–3.
answer =
J
(2 marks)
f
A certain material has a Young modulus greater than copper and undergoes
brittle fracture at a stress of 176 MPa.
On Figure 5 draw a line showing the possible variation of stress with strain
for this material.
(2 marks)
From AQA Physics A PHYA2 Mechanics, Materials and Waves January 2012
(Question 4)
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8