4.8 Materials

• What is elasticity in materials science?

  Returns to original shape
• Plasticity occurs when stress is applied beyond the elastic limit
• Match the property with its description:

  Elasticity ↔️ Returns to original shape

  Plasticity ↔️ Undergoes permanent deformation
• What is the formula for stress?

  $\frac{\text{Force}}{\text{Area}}$
• Match the property with its unit:

  Stress ↔️ Pascal (Pa)

  Strain ↔️ Dimensionless
• The SI unit for strain is N/m².

  False
• What is stress defined as in materials science?

  Force per unit area
• Strain is a dimensionless quantity that measures the deformation of a material
• What does Young's modulus measure?

  Stiffness of a material
• A high Young's modulus indicates a material is very stiff.


  True
• The formula for Young's Modulus is Stress divided by Strain.
• Which material has a high Young's Modulus?

  Steel
• The spring constant 'k' in Hooke's Law represents the stiffness of the material.


  True
• A material with elasticity returns to its original shape after stress is removed.


  True
• Elasticity occurs when stress remains within the elastic limit
• Strain is calculated as the change in length divided by the original length
• Steps to calculate stress and strain:

  1️⃣ Measure the applied force

  2️⃣ Determine the cross-sectional area

  3️⃣ Calculate stress using Force/Area

  4️⃣ Measure the change in length

  5️⃣ Calculate strain using Change in Length/Original Length
• Strain is the measure of deformation resulting from applied stress
• The SI unit for stress is Pascal (Pa).


  True
• Match the property with its formula:

  Stress ↔️ $\frac{\text{Force}}{\text{Area}}$

  Strain ↔️ \frac{\text{Change \in Length}}{\text{Original Length}}
• Young's modulus is calculated by dividing stress by strain
• What does Young's Modulus measure in a material?

  Stiffness
• A high Young's Modulus indicates a material is very stiff.


  True
• Hooke's Law describes the linear relationship between stress and strain within a material's elastic region.
• What is the maximum stress a material can withstand before it deforms permanently called?

  Elastic limit
• What type of deformation occurs in plasticity?

  Permanent
• Stress is the force applied per unit area on a material.
• Strain is a dimensionless quantity.

  True
• What does a high Young's Modulus indicate about a material?

  It is very stiff
• The formula for Young's Modulus is Stress divided by Strain.
• Hooke's Law applies only within a material's elastic region.

  True
• What is the spring constant in Hooke's Law a measure of?

  Stiffness
• Strain is the change in length divided by the original length.
• What does the Ultimate Tensile Strength (UTS) represent in a material?

  Maximum stress before failure
• Match the material property with its example:

  High UTS ↔️ Steel

  Low UTS ↔️ Rubber
• The SI unit for density is kilograms per cubic meter (kg/m³).


  True
• Materials with strong intermolecular forces have higher melting and boiling points.
• Water has a high specific heat capacity, making it an excellent coolant.


  True
• Elasticity occurs within the elastic limit.
• Elasticity refers to a material's ability to return to its original shape after being deformed by stress