2014 Notes from the Marking Centre – Engineering Studies
Introduction
This document has been produced for the teachers and candidates of the Stage 6 Engineering Studies course. It contains comments on candidate responses to particular parts of the 2014 Higher School Certificate examination, highlighting candidates’ strengths and indicating where they need to improve.
This document should be read along with:
- the Engineering Studies Stage 6 Syllabus
- the 2014 Higher School Certificate Engineering Studies examination
- the marking guidelines
- Advice for HSC students about examinations
- other support documents developed by the Board of Studies, Teaching and Educational Standards NSW to assist in the teaching and learning of Engineering Studies in Stage 6.
Question 21
Candidates showed strength in these areas:
- contrasting the operation of two means of public transport (part a)
- applying engineering knowledge and principles to new situations (parts a and c)
- demonstrating understanding of Bernoulli’s principle of fluid mechanics in relation to the operation of a hydrofoil (part b)
- demonstrating understanding of the principles of corrosion protection (part d).
Candidates need to improve in these areas:
- using technical language (part b)
- using the detail provided to outline an engineer’s design criteria (part c)
- demonstrating understanding of the galvanic series in determining anodic/cathodic reactions (part d).
Question 22
Candidates showed strength in these areas:
- demonstrating understanding of truss analysis to determine the reactions at a support (part ai and part aii)
- resolving two components into a resultant force with magnitude and direction (part ai)
- applying a factor of safety to determine an allowable stress (part aiii)
- recognising hot and cold rolling and identifying the resultant grain structure (part bi)
- identifying the changes in mechanical properties caused by hot or cold rolling of steel (part bii).
Candidates need to improve in these areas:
- ensuring all components are used in a moment equation (part ai)
- applying a perpendicular distance to the correct force (part ai)
- calculating internal forces in members of a truss (part aii)
- recognition of a redundant member in a truss (part aii)
- substituting compatible units into calculations (part aiii)
- using the correct terminology of grain structure and mechanical properties (parts bi and bii)
- understanding how a change in grain structure affects the mechanical properties (part bii).
Question 23
Candidates showed strength in these areas:
- identifying the advantages of polymer guttering (part a)
- naming PVC as an appropriate polymer for extruded guttering (part b)
- understanding the basic principles involved in extrusion and identifying parts of the process (part b)
- identifying where corrosion was likely to have occurred (part c).
Candidates need to improve in these areas:
- outlining the advantages of polymer roof guttering rather than identifying (part a)
- using technical terminology in describing the extrusion process (part b)
- identifying the anode and cathode that correlates to the area(s) of corrosion (part c)
- determining true lengths and applying these correctly to triangulation – then using triangulation to construct true shapes in development (part d)
- constructing transition pieces accurately (part d).
Question 24
Candidates showed strength in these areas:
- attempting methods other than moments to solve a problem (part a)
- outlining a feature of the pitot tube (part b)
- recognising the functions of winglets (part c)
- outlining the features of both turbofan and turbojet engines (part d).
Candidates need to improve in these areas:
- recognising when a question can be solved using a moment equation (part a)
- setting out calculations (part a)
- determining where to take moments from (part a)
- not confusing flight systems such as airspeed indicator and altimeter (part b)
- understanding how turbofan thrust is created from bypass air and burnt gases (part d).
Question 25
Candidates showed strength in these areas:
- demonstrating understanding of control technologies relating to car safety (part a)
- outlining methods of electrical storage in a car (part b)
- outlining the advantages of fibre optics as a medium for communication (part c)
- recognising triangulation (part d).
Candidates need to improve in these areas:
- understanding how electricity is generated in a transport electrical system (part b)
- understanding how voltage can be changed in an electrical system (part b)
- understanding the role of satellites and the method of calculating distance from a satellite (part d).
Question 26
Candidates showed strength in these areas:
- manipulating the potential energy formula (part ai)
- recognising notch toughness as the property determined by an impact test (part aii)
- attempting to sum forces on an inclined plane (part bi)
- using the power formula to calculate a value (part bii).
Candidates need to improve in these areas:
- using correct SI units to give an answer with the correct order of magnitude (part ai)
- recognising the key features of the notched bar impact test (part aii)
- understanding the role of friction (part bi)
- considering using both free body diagrams and graphical solutions to solve inclined plane friction problems (part bi)
- manipulating power and efficiency to determine the power required in a given situation (part bii).
Question 27
Candidates showed strength in these areas:
- assembling components
- understanding orthographic views
- calculating sizes to help determine the overall shape of what was to be drawn
- positioning certain features (in particular the threaded holes)
- dimensioning the overall length.
Candidates need to improve in these areas:
- sectioning to AS1100 standards
- knowing the sizes for nuts and washers
- dimensioning a sphere
- showing threads to AS1100 standards
- sectioning/hatching standards for nuts and washers as per AS1100.
NSW Government