AQA
A-level
PHYSICS
7408/3BC
Paper 3 Section B Engineering physics
Version: 1.0 Final
*JUN2374083BC01*
IB/M/Jun23/E7 7408/3BC
For Examiner’s
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Question Mark
1
2
3
4
5
TOTAL
Thursday 15 June 2023 Morning
Materials
For this paper you must have:
• a pencil and a ruler
• a scientific calculator
• a Data and Formulae Booklet
• a protractor.
Instructions
• Use black ink or black ball-point pen.
• Fill in the boxes at the top of this page.
• Answer all questions.
• You must answer the questions in the spaces provided. Do not write
outside the box around each page or on blank pages.
• If you need extra space for your answer(s), use the lined pages at the end of
this book. Write the question number against your answer(s).
• Do all rough work in this book. Cross through any work you do not want
to be marked.
• Show all your working.
Information
• The marks for questions are shown in brackets.
• The maximum mark for this paper is 35.
• You are expected to use a scientific calculator where appropriate.
• A Data and Formulae Booklet is provided as a loose insert.
Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
A-level
PHYSICS
Paper 3
Section B Engineering physics
Time allowed: The total time for
both sections of this paper is
2 hours. You are advised to
spend approximately
50 minutes on this section.
2
*02*
IB/M/Jun23/7408/3BC
Section B
Answer all questions in this section.
0 1 . 1 One equation used in translational dynamics is:
force = mass × acceleration
State in words the equivalent equation used in rotational dynamics.
[2 marks]
Figure 1 shows two identical uniform plates A and B. The axis of rotation of each
plate is shown.
Figure 1
0 1 . 2 State and explain which plate has the greater moment of inertia about its axis
of rotation.
[2 marks]
Do not write
outside the
box
3
*03*
Turn over ►
IB/M/Jun23/7408/3BC
Do not write
outside the
An electric motor drives a machine that punches out plates from a box long strip of
sheet metal. The motor runs continuously and is fitted with a flywheel.
Figure 2 shows how the angular velocity ω of the flywheel varies with time t.
Figure 2
Table 1 describes the sequence for the machine after it has been brought up to
speed ωA.
Table 1
A The punching operation starts.
A to B The flywheel transfers some of its energy during the punching operation.
B to C The flywheel is again brought up to speed ωA by the motor.
C The next punching operation starts.
0 1 . 3 A new flywheel with a greater moment of inertia is fitted in place of the original
flywheel. The motor torque is constant and the same as before.
Sketch on Figure 2 a graph showing how the angular velocity varies with time for the
machine fitted with the new flywheel.
Assume that:
• the punching operation starts at the same angular speed ωA
• the same quantity of energy is transferred when punching the metal sheet.
[2 marks]
Question 1 continues on the next page
4
*04*
IB/M/Jun23/7408/3BC
Do not write
outside the
0 1 box . 4 Explain one difference between your graph and the original graph.
[1 mark]
7
5
*05*
Turn over ►
IB/M/Jun23/7408/3BC
Do not write
outside the
0 2 box Figure 3 shows a heavy stone grinding wheel used for sharpening tools.
Figure 3
The pedal is connected to the axle of the wheel by a connecting link and crank.
The operator pushes the pedal downwards to accelerate the wheel from rest.
The wheel begins to rotate in the dire [Show Less]