Materials - S01 - S05

• what is meant by accurate


  How close a result is to the true value
• what is meant by precise

  How close repeated results are to one another
• What is meant by errors


  Difference between an individual result and the true value
• What is meant by uncertainty


  estimate of the range of values within which the true value lies for a measurement
• Density equation 


  p = m/v
• What is Hookes law and its equation 


  Hookes law states the extension of a spring is proportional to the applied force up to the limit of proportionality of the spring

  F = k x (change in)L
• what is meant by the elastic limit of the wire


  It is the maximum extension for the wire to return to its original shape
• What is meant by plastic deformation

  Permanent extension
• K = spring constant
• What is stress


  It is the force per unit area

  stress = F/A
• What is strain


  It is the change in length

  strain = x/L
• Energy stored equation


  E = 1/2 x F x change in length
• What is tensile stress


  Tensile stress is defined as the tension per unit cross-sectional area
• What is tensile strain

  tensile strain is defined as the extension per unit original length
• What is youngs modulus

  It is defined as the tensile stress per unit tensile strain

  • it is the measure of a materials stiffness
• Youngs modulus is the gradient of the linear region of a stress vs strain plot

  -it is the Ratio of tensile stress to tensile strain
• What is yield stress

  It is the point at which a large amount of plastic deformation occurs with a constant or reduced load
• What is the limit of proportionality


  It is the point at which the material stops obeying hookes law
• What is the fracture stress


  It is the stress at which the material fails via fracture
• What is the elastic limit


  The point beyond which the material would no longer return to its original shape and size once the load is removed
• What is the ultimate tensile stress

  it is the maximum stress that a material can withstand