Elasticity and Hooke’s law of elasticity

Elasticity and Hooke’s law of elasticity

What is Elasticity?

It is the property of a body by virtue of which body tends to regain its original shape and size after unloading. and the deformation called elastic deformation. for example steel, rubber, concrete and quartz. The Elastic behavior of materials plays an important role in engineering design.

Here are 10 daily life examples of elasticity:

1. Stretching a Rubber Band: When you stretch a rubber band, it elongates and returns to its original shape when released.
2. Bouncing a Basketball: When you bounce a basketball, it deforms upon hitting the ground and then regains its original shape as it rebounds.
3. Compressing a Spring: When you compress a spring, it stores potential energy, and when released, it expands back to its original length.
4. Squeezing a Stress Ball: Stress balls are designed to be elastic and regain their shape after squeezing.
5. Using a Trampoline: When you jump on a trampoline, the surface stretches and bounces you back up due to its elasticity.
6. Pulling on a Hair Tie: Hair ties stretch to hold your hair in place and return to their original state when removed.
7. Stretching a Balloon: Inflatable balloons expand when filled with air and contract when the air is released.
8. Using an Elastic Waistband: Elastic waistbands on clothing expand to fit comfortably and retract to their original size.
9. Bouncing on a Diving Board: Diving boards flex under your weight and then spring back, propelling you into the water.
10. Playing with Silly Putty: Silly Putty can be stretched and molded into various shapes, then return to its original form over time.

Stress :-

When body is subjected to an external applied force, an internal resistance devloped in the body or by the body in elemental area. The internal resistance is known as stress. Stress will generate in any body if strain is resisted.

Strain :-

Strain is the deformation that is induced in any object. It expressed in unit length. Strain is a ratio and it is unitless and dimensionless quantity.

It is represented by Strain= Deformation/ Length ε = △/L

There are three types of strain – longitudinal strain, shear strain and volumetric strain.

Hooke’s Law of elasticity

Stress and strain are directly proportional to each other within the proportional limit. This is called Hooke’s Law.

Stress ∝ Strain σ∝ε σ=Eε E = σ/ε Where, E = young modulus of elasticity ε = strain σ = stress Unit of young modulus is pascal

Frequently Asked Questions:

 

1. The property of a body, by virtue of which it tends to regain its original size and shape when the applied force is removed, is known as________

A) Elasticity
B) Plasticity
C) Viscosity
D) Rigidity

ANSWER= (A) Elasticity
Explain:-
Check Answer

 

2. Which of the following substance has the highest elasticity ?

A) Rubber
B) Steel
C) Sponge
D) Copper

ANSWER= (B) Steel
Explain:-
Check Answer

 

3. Hooke’s law states that within the elastic limit _________ is proportional to strain.

A) Weight
B) Force
C) Stress
D) Elastic moduli

ANSWER= (C) Stress
Explain:-
Check Answer

 

4. Modulus of elasticity depends upon:

A) Stress
B) Strain
C) Applied force
D) None of these

ANSWER= (d) None of these
Explain:-
Check Answer

 

5. Hooke’s law essentially defines:

A) Stress
B) strain
C) Elastic limit
D) None of these

ANSWER= (C) Elastic limit
Explain:-
Check Answer

 

6. Unit of stress is same as that of:

A) Force
B) Pressure
C) Work
D) Energy

ANSWER= (B) Pressure
Explain:-
Check Answer

 

7. What is strain ?

A) ratio of change in dimension to original dimension
B) ratio of change in length to original area
C) force per unit area
D) change in length of a body

ANSWER= (A) ratio of change in dimension to original dimension
Explain:-
Check Answer

 

8. Which of the following is a dimensionless quantity ?

A) Force
B) Stress
C) Pressure
D) Strain

ANSWER= (D) Strain
Explain:-
Check Answer

 

9. Which of the following physical quantities represent stress?

A) Force/Length
B) Energy / Area
C) Impulse / Volume
D) Restoring Force / Area

ANSWER= (D) Restoring Force / Area
Explain:-
Check Answer

 

10. The unit of stress is:

A) kg/mm^2
B) poise
C) N/m^2
D) none of these

ANSWER= (C) N/m^2
Explain:-
Check Answer

Read Also-

• Fundamental quantities and its units
• Force, its types and its units
• Motion and it’s type
• Pressure and it’s Unit
• Surface Tension and it’s applications
• Heat transfer and Modes of heat transfer

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