BCGBC4010A Apply structural principles to residential low-rise constructions

Structural principles - Properties

Topic activity
Question 1 of 8
What does the centroid tell us about a structure?
A.	The line of symmetry
B.	The best place to position service holes
C.	The centre of gravity
D.	The position where service holes should be avoided
E.	The point where stresses will be greatest
The correct answer is C - The centre of gravity.

Question 2 of 8
What is the second moment of area?
A.	Moment of inertia
B.	A section property which disregards the material's strength
C.	The ability of a shape to resist bending
D.	All of the above
E.	None of the above
The correct answer is D - All of the above. All of these describe the second moment of area.

Question 3 of 8
What is the second moment of area I about the x-x axis for a section 250 mm high x 50 mm wide?
A.	2.6 x 106 mm3 
B.	26 x 106 mm4
C.	2.6 x 106 mm4
D.	65 x 106 mm4
E.	65 x 106 mm3
The correct answer is D - 65 x 106 mm4.

Question 4 of 8
What is the section modulus?
A.	A measure of the stiffness of the shape
B.	A section property which disregards the material's strength
C.	The ability of a shape to resist bending
D.	All of the above
E.	None of the above
The correct answer is E - All of the above. All of these are descriptions of the section modulus.

Question 5 of 8
What is the section modulus Z for a beam 250 mm high x 50 wide about the x-x axis?
A.	5.2 x 103 mm3 
B.	26 x 103 mm3
C.	520 x 103 mm3
D.	5.2 mm3
E.	5.2 x 106 mm4
The correct answer is C - 520 x 103 mm3.

Question 6 of 8
Which best describes the radius of gyration?
A.	It is used to predict the buckling in a slender column
B.	It is used to work out the deflection of a beam
C.	It is the same as Young's modulus
D.	It is used to predict the crushing in a short column
E.	It is used to work out how much a column will rotate under load 
The correct answer is A - It is used to predict the buckling in a slender column.

Question 7 of 8
What is the least radius of gyration for a timber post with cross-sectional dimensions of 90 mm x 180 mm?
A.	82 x 103 mm3 
B.	26 mm
C.	16.4 x 103 mm3
D.	52 mm
E.	6.7 x 103 mm3 
The correct answer is B - 26 mm.

Question 8 of 8
Which of the following pairs of mechanical properties are the reverse of each other?
A.	Ductility and elasticity
B.	Brittleness and hardness
C.	Malleability and ductility
D.	Strength and toughness
E.	Elasticity and plasticity
The correct answer is E - Elasticity and plasticity. Plasticity is the reverse of elasticity.

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