what is elasticity?
what is stress strain curves?
what is elastic limit?
what is strength?
what is yield point?
what is plastic deformation?
Elasticitiy is the ability of material to return to its original shape after the force causing deformation is removed
-Stres strain curve A graph showing how a material responds to force, with stress (force per area) on the y-axis and strain (extension ratio) on the x-axis. It shows elastic region, yield point, plastic region, and fracture.
-Elastic limit is the maximum stress a material can experience and still return to its original shape once the force is removed.
-Strength is how much stress a material can withstand before it breaks,stronger material has higher.
-Yield point this is where the material stops behaving elastically and begins to deform permananently with little or no extra force.
-Plastic deformation is when a material is stretched beyond the elastic limit causing permanent shape change even after the force is removed.
what is creep?
what is fatigue?
what is ductility?
what is brittleness?
what is malleability?
what is elastic hysterisis?
-Creep when a material under stress deforms gradually over time
-Fatigue matericals can become brittle and then fall overtime due to repeated stress being applied
-Ductility is the ability of a material to be drawn into new shapes by tenssile forces
-Brittleness is the tendencey of a material to fracture under stress
-Malleability is the ability of a material to be formed into new shapes by compressive forces
-Elastic hysteresis occurs in materials like rubber where energy is lost as heat due to internal friction between large molecules, causing different stress–strain curves during loading and unloading.
what is eqaution for density?
what does high density mean?
what does a low density mean?
what can density change with?
-Density describes how much mass is packed into a given volume of a substance
-Formula: density (ρ) = mass ÷ volume
-Written as: ρ = m / V
-Mass (m) is measured in kilograms (kg)
-Volume (V) is measured in cubic metres (m³)
-Density is measured in kg m⁻³
-A high density means particles are closely packed (e.g. metals, bone)
-A low density means particles are more spread out (e.g. gases, fats)
-Density can change with temperature (heating usually decreases density)
-Density can change with pressure, especially in gases
what is stiffness?
what happens if we stretch a wire?
-A stiff material does not deform very much when force is applied
-Rubber isn’t stiff
-Steel is a stiff material
-K=stiffness of a spring or wire
-E=stiffness of a material
-If we stretch a wire as long it does not go pass the elastic limit it will behave the same way obey hookes law.
-We can say what the stiffness of the wire is
-This is not the same as saying what the stiffness of a material is.The stiffness of a wire will depend on its dimensions.Its length and cross-sectional
what is the area under the graph equal to?
what are the equations?
-Elastic strain energy is the energy stored in a material when it is stretched or compressed, as long as it is within the elastic limit.
-The area under the graph is equal to the amount of work that was done stretching the spring/wire
-If the wire behaves elastically then this energy is stored as elastic potential energy or strain energy
Equations
Alternative
E=1/2kx^2
E=elastic strain joules
K=spring constant (Nm-1)
X=extension or compression (m)
Work done for elastic strain showing when a material is compressed
E=1/2Fx
F=force applied (N)
X=extension or compression (m)
Hookes law
what is hookes law?
what is the equation?
what does it state?
what does a larger K mean?
where does it only apply to?
what happens when the force is removed?
-Hooke’s Law describes how a material stretches or compresses when a force is applied
-It states that force is directly proportional to extension, as long as the elastic limit is not exceeded
-Formula: F = kx
-F = force applied (newtons, N)
-k = spring constant, measures stiffness (N m⁻¹)
-x = extension or compression (metres, m)
-A larger k value means a stiffer spring or material
-Hooke’s Law only applies in the elastic region
-When the force is removed in the elastic region, the material returns to its original length
-The limit of proportionality is where the force–extension graph stops being a straight line
-On a force–extension graph, Hooke’s Law is shown by a straight line through the origin
-The gradient of the force–extension graph is the spring constant (k)
Stress and Strain:
what is stress and the formula?
what is strain and the formula?
-Stress tells you how much load a material can safely take before failing.instead of using tensile or compressive.
-Tensile stress: pulling/stretching force
-Compressive stress: pushing/squeezing force
-Stress determines the breaking of materials.High stress leads deformation
-force/area
-Stress = pascals (Pa or N m⁻²)
-Force (F) = newtons (N)
-Area (A) = square metres (m²
-Strain is change in length divided by the original length.
-how much a material stretches or compresses under stress.
-They have no units because both lengths are in metres so it cancels out
-Tensile strain: material gets longer.
-Compressive strain: material gets shorter.
-Larger strain = material stretches more under the same force.
Formula
deltax/L
-Extension (Δx) = metres (m)
-Original length (L) = metres (m)
Young modulus:
what is young modulus?
what is defined as on the graph?
what happens on the graph?
what is equation
-Stress/strain equation
Stress-nm-2 or pa
Strain-no units
-Young modulus-Pa (N m⁻²)
Young’s Modulus measures a material’s stiffness
-Defined as the ratio of stress to strain in the elastic region
-Only valid up to the limit of proportionality
-In the elastic region, materials return to their original shape
-On a stress–strain graph, Young’s Modulus is the gradient of the straight-line section
-Steeper gradient → higher Young’s Modulus → stiffer material
-Shallower gradient → lower Young’s Modulus → more flexible material
