Tiêu đề TOPIC 6 MECHANICAL PROPERTIES OF MATTER - WazaElimu.com.pdf ✅

48 Proportionality limit: This is the limit where material return to its original shape and size after the deforming force is removed. Hooke’s law: This law states that: “Within elastic limit, extension is directly proportional to tension (force)” OR “Within elastic limit, the extension is directly proportional to tension, provided that the elastic limit is not exceeded”. Elastic limit  This is the limit at which beyond this Hooke’s law does not obeyed and the material cannot return to its original shape and size. Example at point AY At point B = Plastic deformation Here the materials undergo permanent deformation under the action of external force. At point C = Breaking point At this point, when external force is applied the materials will break. NOTE: From Hooke’s law Force applied (F) α Extension (X) of the spring F α X F = KX Therefore; Where by K = Elastic force constant and its SI-Unit is N/m F = Tension (Force) and its SI-Unit is Newton (N) X = Extension and its SI-Unit is metre (m) APPLICATION OF ELASTICITY IN REAL LIFE  At home: Elasticity is applied in:-  Rubber gasket that seal the refrigerator door  Clothing  Spring in furniture  Rubber bands that hold things together  Toys like balloons and balls.  In transport: Elasticity is applied in:-  Rubber tyres, hoses, belts and shock-absorbing springs for cars and trucks.  Airplane wings  Support cables for bridges K = F X