Welcome back kpoki — been a while! Let's pick up where you left off.
Here are the solutions to the questions you provided:
Question 8: The bulk modulus of a material is most relevant when analyzing:
The bulk modulus measures a material's resistance to compression under uniform pressure.
- A. A wire under tension (relates to Young's modulus)
- B. A solid cube under uniform pressure from all sides (relates to bulk modulus)
- C. A rod being twisted about its axis (relates to shear modulus)
- D. A beam supported at both ends with a central load (relates to Young's modulus and shear modulus)
The correct option is B.
B.Asolidcubeunderuniformpressurefromallsides
Question 12: In the equation for thermal stress, σ=YαΔT, the term α represents:
The equation for thermal stress relates stress (σ) to Young's modulus (Y), the change in temperature (ΔT), and the material's coefficient of thermal expansion (α).
- A. Coefficient of friction
- B. Coefficient of linear expansion
- C. Thermal conductivity
- D. Specific heat capacity
The correct option is B.
B.Coefficientoflinearexpansion
Question 11: A bone with Young's modulus 1.50×1010N/m2 has a minimum effective cross-sectional area of 2.50cm2. If a force exceeding this causes fracture, what is the maximum force the bone can withstand?
Assumption: The Young's modulus given is intended to be used as the ultimate tensile strength (fracture stress) for the purpose of this problem, despite it being a measure of stiffness.
Step 1: Convert the cross-sectional area to square meters.
A=2.50cm2=2.50×(10−2m)2=2.50×10−4m2
Step 2: Use the formula for stress, σ=AF, to find the maximum force Fmax.
Fmax=σ×A
Substitute the given values, using Young's modulus as the fracture stress.
Fmax=(1.50×1010N/m2)×(2.50×10−4m2)
Fmax=(1.50×2.50)×10(10−4) N