Engineering Studies 2021 HSC exam pack

Students should:

• read the question carefully to ensure that they do not miss important components of the question
• avoid simply re-stating the question in their response
• have a clear understanding of key words in the question and recognise the intent of the question and its requirements
• engage with any stimulus material provided and refer to it in the response
• communicate ideas and information using relevant examples
• expect to perform some mathematical functions, interpret data/graphs/tables and assess information for accuracy, reliability and/or validity
• consider using graphical solutions if appropriate
• review their response to ensure that it addresses the question requirements.
• include all working in calculation responses, set out in a logical manner
• be familiar with relevant engineering terminology and use correctly to enhance their answers
• use correct materials terminology when speaking of engineering materials, for example, most uses of aluminium are in alloyed form so students should be writing “aluminium alloys” to make it clear they understand aluminium is being used in an alloyed form
• calculate the area of circle using the formula: pd²/4 because in Engineering Studies using diameters as opposed to radii in calculation problems is more common
• ensure the use the drawing equipment to maximise their performance all drawing questions across the examination.

Question 21

Student should:

• understand the impact of structures upon society and the environment (a)
• become familiar with AS1100 Standards(bi)
• demonstrate knowledge of orthogonal drawings to AS 1100 Standards (bi)
• be familiar with scale (bi)
• use the formula sheet to access appropriate formula (bii)
• understand the different types of stress and Factor of Safety (bii)
• recognise the difference between MPa and kN (bii)
• show understanding of the difference between a macrostructure and microstructure (c)
• clearly labels diagrams (c).

In better responses, students were able to include some of the following:

• correctly apply the key word ‘outline’ (sketch in general terms) (a)
• differentiate between the construction and the use of a bridge (a)
• connect social issues to the construction/presence of a large bridge (a)
• understand thread requirements (bi)
• correctly draw a complete bolt (bi)
• arrange the formula to get the appropriate answer/s (bii)
• identify and label all the constituents of reinforced concrete (c)
• generate descriptive diagrams with quality labelling (c).

Areas for students to improve include:

• ensuring TWO different issues are clearly addressed (a)
• clearly relating issues to how they impact society (a)
• revising standard sizes of nuts, bolts and washers (bi)
• drawing items accurately (bi)
• working in required SI units (bii).  

Question 22(a)

Student should:

• use projection to transfer measurements from existing orthographic views (a)
• use all supplied graphical information to interpret the correct details of the object being drawn (a)
• use comparative terms to identify advantages of pressure die casting (b)
• consider the manufacturing requirements of the item being cast (b)
• apply the data to the supplied formula (c)
• rearrange the formula to find current (c)
• recognise the types of energy present in the given scenario (d)
• use appropriate formulae to calculate speed (d).  

In better responses, students were able to include some of the following:

• represent holes on inclined faces of the top view as ellipses (a)
• correctly incorporate a range of appropriate line types in the top view (a)
• relate the materials used for a mould to the resulting cast surface finish (b)
• differentiate between single use and multiple use casting applications (b)
• demonstrate an understanding of the industrial applications of both methods (b)
• correctly calculate current (c)
• recognise that battery capacity is a product of current and time (c)
• apply the appropriate time unit of seconds to calculate capacity (c)
• calculate the potential energy at A (d)
• calculate the work done by friction on the skateboard (d)
• deduct frictional work from potential energy (d)
• equate net energy at B to the kinetic energy formula to find speed (d)
• calculate the net force acting down the plane (d)
• use Newton's Second Law to find acceleration down the plane (d)
• use equations of uniformly accelerated motion to find speed (d).

Areas for students to improve include:

• using the included 45-degree line to project measurements from the side view (a)
• including centre lines for all circles and ellipses in orthographic views (a)
• interpreting elliptical shapes for circular holes on inclined faces (a)
• closely inspecting the front and side view to confirm all required details in the top view (a)
• identifying the advantage of an improved material property (b)
• understanding the different grain structures of cast components (b)
• using scientific notation correctly (c)
• recognising that frictional work reduces the energy remaining at B (d)
• calculating the correct value of frictional work (d)
• resolving the components of weight parallel and perpendicular to the plane (d)
• understanding that the scenario did not involve limiting friction (d).

Question 23

Student should:

• apply their understanding of materials to an unfamiliar situation (a)
• be familiar with general material physical properties (a, b)
• understand how the immediate environment impacts the service life of a product (a)
• be able to identify the tasks included in the role of an engineer (b)
• be able to use engineering mathematical principles to calculate resulting forces within a system (c)
• use their knowledge to describe benefits of in-service (use)and manufacturing properties (d).

In better responses, students were able to:

• use correct engineering principles to provide a clear and correct answer.
• provide examples to enhance their answer (a, b, c)
• set their work out, logically and clearly, ensuring all areas were covered appropriately.

Areas for students to improve include:

• using correct terms, particularly when referring to forming techniques and characteristics
• showing knowledge of the principles of level flight at a constant speed
• applying engineering principles to a presented scenario appropriately
• demonstrating knowledge of what constitutes a free-body diagram.

Question 24

Student should:

• answer using basic principles supported by uses (c)
• learn AS1100 associated with sectioned orthogonal drawings (d)
• understand symbols and notations used on orthogonal drawings (d). 

In better responses, students were able to include some of the following:

• clearly differentiated how performance features of 2.4 GHz and 5 GHz networks differ (a)
• clearly identify how and why the two networks’ frequencies differed by performance
• compare the range, bandwidth, attenuation and interference with examples (a)
• correctly identify either a voltmeter or multimeter connected across the circuit/component (b)
• identify the multimeter set to the correct scale connected in parallel (b)
• state that LEO satellites were close to the Earth (160 km – 2000 km altitude) and fast moving (>25,000 km/h) and that enables low latency, low powered telecommunications (c)
• indicate an understanding of Low Earth Orbit (LEOs) compared to other satellite systems (c)
• draw all the necessary lines to complete the drawing including a countersunk hole (d)
• assemble the components correctly (d)
• indicate the sectioned surfaces correctly (d).

Areas for students to improve include:

• using examples to justify/support responses (a)
• not just including a list of uses (a)
• identifying a practical task instead of describing the use of a calculation (b)
• responding to an outline question in the correct way (b)
• learning the correct meters for such an application, not incorrectly describing the use of an ammeter (b)
• a better understanding of the different satellites (c)
• a better understanding of the basic principles of each type of satellite, for example, those for GPS and those for low latency telecommunications (c)
• deepening their knowledge of AS1100 drawing standards (d)
• knowing the ‘how/why’ to indicate different materials on the section plane (d)
• understanding how to assemble components to complete an assembly drawing (d).

Question 25

Student should:

• recognise that a control system takes inputs, interprets them and then delivers an output. It is not simply a mechanism, it controls a system
• recognise that the reaction at A is the same direction as the member AC because only one member is attached at the support (b)
• apply moments or concurrent forces to arrive at a solution, even a partial solution is better than a non-attempt as it shows some engagement and understanding of interpreting the question (bi)
• draw a free-body diagram to assist when they are answering mechanics questions. At Joint A, a free-body diagram would have assisted students to interpret the situation, and hence determine the angle of member AC, and the force within (bii).

In better responses, students were able to include some of the following:

• outline the principle behind the operation of one control technology providing an input into the processor which then provided an output where some action was taken. Most students related this to a system in a modern car. Some examples included ABS (anti-lock braking systems), lane assist, adaptive cruise control and autonomous vehicle operation (a)
• recognise and take moments about point B to find the horizontal reaction at A using correct units (bi)
• use a triangle of forces or the sum of horizontal forces and calculate the internal reaction of AC and the nature of this force (bii)
• indicate a relevant section plane and then showed working taking moments about a joint considering only one part of the truss. Students did find the correct answer summing vertical forces indicating the nature of force CE (biii)
• understand how the process of normalising changed the internal structure of the pins to a finer less stressed equiaxed grain structure. They identified this process led to an improvement in the material properties of the pins (c).

Areas for students to improve include:

• understanding what a control system is and what role this technology plays in various cases. Students need to understand that sensors are often used to gather provide input information to the processor. This determines what action needs to be taken, that is, output. An example would assist in outlining how the control system works. Many students confused mechanisms with control systems and stated the mechanical operation of the brakes or the turning of the steering wheel was a control system (a)
• identifying which point on the truss moments should be taken to determine the correct horizontal reaction at point A. Students need to understand only perpendicular distances from that point should be used in this calculation (bi)
• using a free body diagram to sketch the force polygon of the joint they are using which leads on to trigonometry calculations to find the relevant angles and answer. A basic understanding of how to apply trigonometry was often missing in some responses (b ii)
• using an appropriate section plane marked on the drawing and demonstrated in their calculations which part of the truss was not considered. An understanding of moments is necessary to find the internal member AC. Many students could not indicate a section plane (b iii)
• understanding the heat treatment process and that the grain structure will change affecting the properties of the material in this process. Students mentioned many properties that were not relevant or properties that contradicted each other demonstrating limited understanding (c).

Question 26

Student should:

• calculate the angle of repose and apply an appropriate trigonometry function (b)
• clearly explain how a mobile phone maintains communication with the network (c)
• communicate ideas and information using relevant drawings to support answer (d)
• compare multimode and single mode optical fibre in relation to light paths taken and materials used (d).

In better responses, students were able to include some of the following:

• outline a relevant technology to support fuel efficiency (a)
• manipulate the given data and units correctly in calculations (b)
• bypass the need to use a FBD when converting mu (µ) to theta (b)
• apply appropriate calculation operations that incorporate the angle of repose and trigonometry (b)
• correctly relate the mobile phone communication link with the network (c)
• correctly compare two light paths and materials used (d)
• support the answer with a correct drawing that clearly demonstrates the different light paths required for single and multimode optical fibres (d).

Areas for students to improve include:

• determining the angle of repose prior to determining the height (h) using appropriate trigonometry (b)
• using the correct trigonometric ratio (sine) to calculate h (b)
• understanding of mobile-phone connectivity and continuity of calls (c)
• stating key points (before relating cause and effect), for example, cell towers connect through a radio wave frequency (c)
• relating the response to key words in questions, that is, optical fibre materials, not insulation material (d)
• not confusing many paths-in-a-fibre with many-fibres-in-a-path (d)
• an understanding of transmission, material and structural properties of optical fibres (d)
• mentioning the materials used, not just listing light paths (d).

Question 27

Student should:

• link the drawing methods
• give examples of how each drawing method in used in engineering clearly showing the uses of each type
• identify the difference between freehand sketching for communication as opposed to a free-body diagram.

In better responses, students were able to include some of the following:

• mention that freehand sketching is the start of the designing process usually with no or minimal measurements included
• link freehand drawing to technical and computer aided drawing (CAD) and differentiate between each type of drawing, showing how each is different in its use
• understand that technical drawing can be done on paper and CAD encompasses technical drawing
• technical drawing seeks to fully define the object
• use good examples of drawings in different stages
• describe the workflow throughout the technical drawing process
• understand what AS1100 is and how it can help engineers communicate accurately
• realise that standards provide the benefit of unambiguity and clarity
• that standards provide a set of rules that enable understanding and collaboration with designers, engineers, technicians and trades people
• explain the uses of CAD – editing, sharing, modelling, simulating, and manufacturing
• CAD provides analysis tools such as simulation, material requirement calculations, finite element analysis.

Areas for students to improve include:

• remembering that ‘examples’ implies more than one example
• understanding AS1100 is an Australian Standard and the nature of its role
• understanding standards are used as a common drawing language
• understanding the uses and limitations of each type of drawing
• an awareness that technical drawings provide information on dimensions and views of an object
• understanding the many uses of CAD tools
• understanding that drawing is part of the process of design, prototyping and manufacturing a product
• being more specific in the examples used
• that technical drawing seeks to fully define an object for manufacture
• realising that CAD encompasses most aspects of technical drawing
• explaining the differences in each drawing type rather than mentioning a progression of difficulty or time usage for each type.