Section 4.2 - Materials Flashcards
What is density?
Density = mass / volume
How to measue the mass of an irregular solid?
- Measure the mass
- immerse the solid in liquid in a measuring cylinder
- observe the increase in the liquid level, this is the volume
- Calculate density
What is Hooke’s law?
Force is directly proportional to extension upto the limit of proportionality.
What is the limit of proportionality?
The point after which Hooke’s law is no longer obeyed.
What is the elastic limit?
is just after the limit of proportionality and if you increase the force applied beyond this, the material will deform plastically.
What is plastic deformation?
Plastic deformation the matrial does not return to its original form once the load is no longer applied
What happens to the spring constant when two springs are put in parallel?
k = k₁+k₂ + ….
What happens to the spring constant when two springs are put in series?
1/k₁ + 1/k₂ + …
What is the energy stored in a spring?
E = 0.5 * Fe
or
E = 0.5 ke²
What is deformation that stretches an object called?
Tensile
What is deformation that compresses and object called?
Compressive
What is the formula for tensile stress?
σ = F/A
What is the formula for tensile strain?
ε = e/L
What is the formula for Youngs modulus?
E = σ/ε
What is the yeild point?
Small increase in tensile stress for a large increase in tensile strain
