Physics Paper 1- Materials

• What causes extension on a spring to occur?

  Tensile forces acting away from the centre of the spring
• What causes compression on a spring?

  Tensile forces acting towards the centre of the spring
• What occurs when a spring experiences too much tensile force?

  Tensile deformation (Tensile forces)

  Compressive Deformation (Compressive forces)
• State Hooke's law

  Force is directly proportional to the extension
• When does hooke's law apply?

  If limit of proportionality is not reached
• What is tensile stress?

  Force per unit area
• what is tensile strain?

  How much a material stretches
• What is elastic deformation?

  When a tensile force is removed, the object will return to original shape
• What is plastic deformation?

  When a tensile force is removed, the object will not return to original shape or length
• How is energy stored during elastic deformation?

  Work done is stored as elastic potential energy
• What is breaking stress?

  The amount of stress a material can withstand without it breaking
• Define a brittle material

  A material which tends to break rather than stretch when a large tensile force is applied
• What is elastic limit?

  A point where plastic deformation occurs and the material does not return to its original shape
• What is the area under a force x extension graph?

  Energy stored in a material
• State young's modulus

  Stress/ Strain
• What is the YM equation?

  FL/AX
• What is a tough material?

  A material that can withstand a large amount of load without breaking
• What is a Ductile material?

  Material that can be stretched into a wire without breaking.
• What is a hard material?

  Can withstand external wear such as scratches or indents without breaking