City Guilds Model Questions Vol1 2021 Engineering Question 5

Practice objective / multiple choice question 5 from the 2021 City Guilds Model Questions Vol1 Engineering examination.

City Guilds Model Questions Vol1 2021 Engineering Objective / Multiple Choice Medium Difficulty
Question 5 CITY_GUILDS_MODEL_QUESTIONS_VOL1 • 2021 • ENGINEERING • objective

A unidirectional composite is made from fibres with modulus \(E_f = 230\) GPa and density \(\rho_f = 2.5\) g cm⁻³, and a matrix with modulus \(E_m = 3.5\) GPa and density \(\rho_m = 1.2\) g cm⁻³. Using the rule of mixtures for longitudinal modulus \(E_c = V_f E_f + (1-V_f)E_m\), determine the fibre volume fraction \(V_f\) required to obtain a composite modulus of 60 GPa. Then calculate the density of the resulting composite.

Answer Options

A. V_f ≈ 0.35 (35 %); density ≈ 1.66×10³ kg m⁻³
B. V_f ≈ 0.45 (45 %); density ≈ 1.80×10³ kg m⁻³
C. V_f ≈ 0.15 (15 %); density ≈ 1.38×10³ kg m⁻³
Correct Answer D. V_f ≈ 0.25 (25 %); density ≈ 1.52×10³ kg m⁻³
Correct Answer
D
Correct Option:
V_f ≈ 0.25 (25 %); density ≈ 1.52×10³ kg m⁻³

About This Question

This is City Guilds Model Questions Vol1 2021 Engineering Question 5. It is one of the objective questions from the 2021 City Guilds Model Questions Vol1 Engineering examination.

Difficulty level: Medium .

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