Solids

Solids

Density
1. Density= m/v
2. ρ
3. Mass per unit volume
Springs
1. Hooke's Law
  1. Extension applied is directly proportional to the load applied
    1. Providing the limit of proportionality is not exceeded!
    2. ΔL ∝ F
    3. F=KΔL
      1. K= Spring constant in n/m
  2. Some materials do not obey, eg. rubber
Young's Modulus
1. Tensile Stress
  1. The perpendicular force applied per unit cross-sectional area
  2. Tensile Stress = F/A
  3. Pa or N/m^2
2. Tensile Strain
  1. Extension produced per unit original length
  2. No units
  3. ΔL/L
3. Ratio of tensile stress applied to tensile strain produced
4. Pa or N/m^2
5. E or Y
6. Stress- Strain graph
  1. Gradient = E
  2. Area underneath = Strain energy per unit volume
Force-Extension Graphs
1. F= EA/L ΔL
  1. EA/l = gradient
  2. E = gradient * l / A
2. Energy Stored
  1. Work Done = Force x Distance
    1. FΔs = Area under graph
      1. = 1/2 b x h
        = 1/2 ΔL x F
        = 1/2 F ΔL
    2. Energy Stored = Work Done
  2. 1/2 F ΔL
Key Terms
1. Limit of proportionality- The point beyond which Hooke's law is no longer obeyed
2. Elastic behaviour- Original size & shape is regained after force is removed
3. Plastic Behaviour- Some permanent deformation when force is removed
4. Elastic Limit - The maximum amount of stretch whilst still regaining original size and shape when force removed
5. Yield Point- The point at which the material 'gives' a little. There is a marked increase in extension due to crystal planes sliding across eachother
6. Ultimate Tensile Strength - The maximum tensile stress that can be applied to a material without it breaking
7. Stiff - Very little deformation when a force is applied
8. Brittle - Very stiff and breaks with hardly any plastic deformation
9. Fracture - Cracks appear on the surface of the solid when a force is applied causing it to break
10. Ductile - Shows plastic deformation

Next up

Description

Resource summary

Similar

	Created by luisnorth about 10 years ago