Mechanical Properties Of Matter Finale Caltec S.6

MECHANICAL PROPERTIES OF MATTER These are properties of materials under the action of forces. 1. Strength: This is the ability of a material to resist breaking when a force is applied e.g. metals N.B: such materials are said to be strong ii) Stiffness: This is the ability of a material to resist change in shape or size when a force is applied to it e.g. chalks dry wood, glass etc. iii) Elasticity: is the ability of a material to regain its original shape and size after its deforming force has been removed. E.g. rubber, spring (metallic) etc. N.B: Such materials are said to be elastic The force applied to stretch the materials is called a tensile force while a force applied to compress a material is called a compressional force. iv) Plasticity: This is the ability of a materials to remain permanently deformed when a deforming force has been removed e.g. plasticine, wet clay etc. v) Ductility: This is the ability of a material to be changed into various shapes without breaking or is the ability of a material to be deformed without breaking e.g. metals. Ductile materials undergo both elastic and plastic for deformation vi) Brittleness: this is ability to break easily or suddenly when a force is applied to it e.g. dry clay, glass, chalk etc. Brittle substances bend very little and then break. Therefore they undergo only elastic deformation with their elastic region being very small. vii) Hardness/ toughness: This is the ability of a material to resist wearing e.g. rubber and metals Hooke’s law This states that the extension produced in a wire is directly proportional to the force applied provided the elastic limit is not exceeded. F= k.e K= K= force constant [k] = = = Units are kgs-2 or Nm-1 Force constant K, is …