Elasticity

Elasticity is the property/ability of a body to return to its original shape and size when deforming force removed

Nb:

i)     A body/substance with ability to undergo elasticity is called elastic substance

ii)    Material are elastic to some degree until elastic limit is reached

iii)  The materials which do not undergo elastic deformation are called brittle substance. For Example, glass, block etc.

iv)  When material deformed beyond elastic limit it become plastic, means it will not regain its original shape even though it doe s not break. This type of deformation is called plastic deformation

v)    Material which undergoes plastic deformation is called inelastic or plastic materials.

Graph of Tension against Extension

Interpretation

i)     Between point O and A

Tension is direct proportional to extension. This was discovered by Hooke and final he comes with law which called Hooke’s law

 

Hooke’s Law

It state that

“Within the elastic limit extension is directly proportional to the force applied”

Or

“Provided that the elastic limit of a body not exceeded the extension is directly proportional to the force applied”

Mathematically:

F α e - remove proportionality constant

F = ke – make K subject

k = F/e

Where:

k = elastic force constant

   = spring constant

F = force applied

e = extension 

SI unit of K is N/m

ii)    At point A

At point A is called limit proportionality or elastic limit

iii)   Between point A and B 

Between Point A and B is called the region of elastic. In this region a small force produces a large extension which is not directly proportional to the extension   

iv)  Between point B and C 

Between Point B and C is called the region of plastic deformation.   At this region material will not return to its original shape and size when applied force/tension/load removed 

v)    Beyond point C

Beyond point C the material breaks

Application of Elasticity In Real Life

A.      Domestic application

i)        Rubber gaskets that seal the refrigerator door

ii)       Clothing

iii)     Springs in furniture

iv)     Rubber bands that hold things together

v)       Toys like balloons and ball

B.      Transport application

i.                     Rubber tyres, hoses, belt and shock

ii.                   absorbing spring for car and trucks

iii.                 Aero plane wings

iv.                 Supporting cable for bridges

C.      Industry application

i)        Conveyor belts

ii)       Measuring weight

iii)     Steel beams in construction

iv)     Insulation of vibration and sound