Unit 4 · External exam revision
Each game plan is a decision routine, a fixed set of questions that takes you from reading a QCAA question to knowing exactly what to do first. Keep the game plans beside you while you work through past papers. The goal is that by the exam you no longer need them.
Start with Game plan 0 every time, because it decides which of the others you need. Go to Game plan 7 before any written question, because the verb decides the shape of the answer. The game plans teach you how to choose a method. The Topic guides teach the content and carry the worked exam questions and practice questions, and each game plan points you to the right one.
Start here
Ask yourself these every time you start an external exam question, in this order. They tell you which game plan to use.
Step 1 · Ask this first
“Am I being asked to calculate, or to write?”
Calculate
Usually Section 3. Work down the question map below and stop at the first yes.
Write
Usually Section 2. Go to Game plan 7 for the shape of the answer, then come back for the content.
Step 2 · If you are calculating
Stop at the first yes
Questions often combine two game plans. Start with the first thing you have to find, then ask the first question again for the next stage. Game plan 5, polymers, has no stop on the map because its questions are written ones that you reach through Game plan 7.
The most common mistake I see in practice exams is calculating when the question asked you to explain, or explaining when it asked for a number. Answer the first question before you pick up your pen.
The full version, with timing, rounding, units and the gaps in the formula book, is Game plan 0, The first question.
Here are the openings of eight real QCAA exam questions. Read each one, ask the first question, and pick the game plan you would reach for. You do not need to solve them.
2025 Question 22 · Section 3 · 8 marks
A child on a sled slides down a snow-covered hill with a 15° incline at an initial velocity of 4 m/s. The combined mass of the sled and the child is 40 kg. The coefficient of kinetic friction between the sled and the snow is 0.35.
Calculate the distance the sled travelled downhill before coming to rest. Include a force diagram to support your response.
2020 Question 23 · Section 3 · 6 marks
An elevator starts from rest and accelerates upwards at a constant rate until the desired velocity of 10 m/s is achieved. The mass of the elevator and occupants is 2500 kg. The tension on the elevator cable is 30 000 N.
Determine the distance the elevator travels during acceleration to the nearest whole unit (m). Include a force diagram with your working.
2025 Question 18 · Section 3 · 4 marks
A bottle opener is used to remove the bottle cap from a glass drink bottle. An effort force of 20 N is exerted on the bottle opener to lift the bottle cap by 2.5 mm. The bottle opener has a velocity ratio (VR) of 16 and is 90% efficient.
a) Calculate the load force on the bottle opener.
2020 Question 19 · Section 3 · 6 marks
A crane requires 4355 W to vertically lift a full scrap metal bin a distance of 20 m from the ground at constant velocity over a period of 90 s.
a) Determine the mass of the full scrap metal bin to the nearest whole unit.
2024 Question 19 · Section 3 · 5 marks
A lead–tin thermal-equilibrium diagram is shown.
a) Determine the composition of the solid and liquid in a 70% lead 30% tin alloy at 200 °C. Annotate the diagram to develop your response.
The diagram is not reproduced here.
2025 Question 14 · Section 2 · 6 marks
A stress–strain diagram for four polymers is shown.
a) Identify the most suitable polymer for applications that require the ability to withstand high stress before deforming plastically. Use two features of the polymer from the diagram to justify your response.
The diagram is not reproduced here.
2025 Question 21 · Section 3 · 9 marks
A conveyor belt system is used to transport packages from a factory to a loading bay, as shown. …
Construct a logic gate circuit for conveyor 2, clearly labelling all inputs and outputs. Complete the corresponding truth table on the next page.
The diagram and the paragraph of conditions are not reproduced here.
2024 Question 16 · Section 2 · 6 marks
During a flood event communities can find themselves isolated, without power and unable to access basic supplies and health care. The risk of further rainfall and submerged roads can hamper rescue efforts.
Explain how mechatronics engineers have used their expertise of control technology, materials science and mechanics to develop machines to benefit communities affected by flood events. Include the type of machine used and two benefits for the community.
Start with Game plan 0 and use Game plan 7 for every written question. Game plans 1 to 6 hold the routines for each topic, and each one links back to the Topic guide sections it draws on.
Game plan 0
The first question
How to work out what any exam question wants, the question map, timing, rounding and what the formula book leaves out.
Reach for it at the start of every question.
Game plan 1
Forces, friction and motion
Inclines, friction, free-body diagrams and the motion equations. The largest topic on the paper.
Reach for it when there is a slope, a coefficient of friction, or a time, distance or acceleration to find.
Game plan 2
Machines and mechanisms
Levers, pulleys, screws, gears, belts and worm drives, with MA, VR and efficiency.
Reach for it when something turns an effort into a load.
Game plan 3
Energy, power and efficiency
Work, power, kinetic and potential energy, efficiency and electrical circuits.
Reach for it when the question names work, power, energy or efficiency, or gives you volts, amps and ohms.
Game plan 4
Metals: diagrams and microstructure
The lever rule, iron–carbon microstructures, plain-carbon steels and heat treatment.
Reach for it when a phase diagram or an iron–carbon diagram is printed, or the question names a steel.
Game plan 5
Polymers and materials selection
ABS, PC and PA6, property tables and stress–strain diagrams.
Reach for it when you have to choose or justify a material from a table or a stress–strain diagram.
Game plan 6
Logic and control
The six gates, truth tables and building circuits from a scenario.
Reach for it when there is a logic circuit, a truth table or a paragraph of conditions for switching a machine on.
Game plan 7
Writing
Cognitive verbs, the seven response templates and the mark budget for Section 2.
Reach for it before any written question.
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