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ENGINEERING, CS 2023 HSC 2 MC

Why did steel replace cast iron in bridges built after 1850 ?

  1. It is lighter in weight.
  2. It is easier to produce.
  3. It has greater tensile strength.
  4. It has greater compressive strength.
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\( C \)

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→ Steel is stronger, more ductile, and has a higher tensile strength compared to cast iron, allowing for the construction of larger and more durable structures.

→ Cast iron generally has greater compressive strength than steel (eliminate D).

\(\Rightarrow C \)

♦ Mean mark 55%.

ENGINEERING, CS 2017 HSC 13 MC

An image of an Allen truss bridge is shown.

Which of the following correctly identifies the loading conditions of an Allen truss bridge?

  1. Timber members in shear and steel members in torsion
  2. Timber members in torsion and steel members in shear
  3. Timber members in tension and steel members in compression
  4. Timber members in compression and steel members in tension
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`D`

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→ Members of a truss can only be in either tension or compression.

→ Steel has very high tensile strength, and although timber has lower tensile strength it has relatively high compressive strength.

→ Therefore D is the only answer that would produce an effective truss.

`=>D`

ENGINEERING, CS 2019 HSC 16 MC

The image shows part of a large anchor recovered from waters off Western Australia. The anchor's approximate date of manufacture was 1790 .
 

This anchor is most likely made from

  1. cast iron.
  2. cast steel.
  3. wrought iron.
  4. laminated silicon steel.
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`C`

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By Elimination:

→ In 1790 mild steel and silicon steel did not exist (eliminate `B` and `D`).

→ Since it is less brittle, wrought iron would have been used as anchors are subjected to sudden impacts against rocks (eliminate `A`).

`=>C`


Mean mark 52%.

ENGINEERING, CS 2019 HSC 11 MC

The table shows materials that have been used to build civil structures over time.

Which row of the table shows the use of the materials in the correct historical order?
 

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`A`

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By Elimination:

→ Stainless steel must have been used after mild steel as it is an alloy of mild steel (not `C` or `D`)

→ Stone was used before iron as it did not require any processes to be formed (not `B`)

`=>A`