materials physics a level Flashcards
revision
What is the definition of stress in materials science?
Stress is defined as force per unit area applied to a material.
What is the formula for calculating stress?
Stress (σ) = Force (F) / Area (A)
True or False: Strain is a measure of how much a material deforms under stress.
True
What is the formula for calculating strain?
Strain (ε) = Change in Length (ΔL) / Original Length (L0)
What does Young’s modulus measure?
Young’s modulus measures the stiffness of a material.
What is the formula for Young’s modulus?
Young’s Modulus (E) = Stress (σ) / Strain (ε)
Fill in the blank: The unit of stress is _____
Pascal (Pa)
What is the relationship between stress and strain in the elastic region of a material?
Stress is directly proportional to strain in the elastic region.
What is the yield point of a material?
The yield point is the stress at which a material begins to deform plastically.
True or False: Beyond the yield point, a material returns to its original shape when the stress is removed.
False
What is plastic deformation?
Plastic deformation is the permanent change in shape of a material when subjected to stress beyond its yield point.
What is the ultimate tensile strength?
Ultimate tensile strength is the maximum stress a material can withstand while being stretched or pulled before necking.
Fill in the blank: The area under the stress-strain curve represents _____
The toughness of the material.
What is the difference between brittle and ductile materials?
Brittle materials fracture without significant deformation, while ductile materials can undergo significant plastic deformation before fracture.
What is a common example of a ductile material?
Steel is a common example of a ductile material.
What does the term ‘elastic limit’ refer to?
The elastic limit is the maximum stress a material can withstand without permanent deformation.
What type of stress is caused by forces acting perpendicular to the surface?
Tensile stress.
Fill in the blank: Shear stress occurs when forces act _____ to the surface.
Parallel
What is the Poisson’s ratio?
Poisson’s ratio is the ratio of lateral strain to axial strain in a deformed material.
What is the typical range of Poisson’s ratio for most materials?
Typically between 0 and 0.5.
What happens to a material when it undergoes cyclic loading?
It can experience fatigue, leading to failure after many cycles of loading and unloading.
True or False: All materials exhibit the same stress-strain behavior.
False
What is the significance of the modulus of resilience?
It measures the maximum energy per unit volume that a material can absorb without permanent deformation.
What type of materials typically have high modulus of resilience?
Ductile materials.
