Elasticity

Card 1: What is elasticity

Elasticity

Elasticity is the ability of a sub-stance to recover its original shape and size after distortion.

Card 2: Forces between atoms

Forces Between Atoms The intermolecular forces consist of an attractive force and a repulsive force.

• At the equilibrium distance d, the attractive force equal to the repulsive force.
• If the 2 atoms are brought closer, the repulsive force will dominate, produces a net repulsive force between the atoms.
• If the 2 atoms are brought furhter, the attractive force will dominate, produces a net attractive force between the atoms.
Card 3: Graph of Resultant Force against the Distance between 2 Atom

Graph of Forces Between 2 atoms x0 = Equilibrium Distance

When the particles are compressed, x < x0, the repulsive force between the particles increases.

When the particles are stressed, x > x0, the attractive force between the particles increases.

If the distance x exceeds the elastic limit, the attractive force will decreases.

Card 4: State Hooke's Law

Hooke's Law

Hooke's Law states that if a spring is not stretched beyond its elastic limit, the force that acts on it is directly proportional to the extension of the spring.

Card 5: What is elastic limit?

Elastic Limit

The elastic limit of a spring is defined as the maximum force that can be applied to a spring such that the spring will be able to be restored to its original length when the force is removed.

Card 6: Equation derived from Hooke's Law

Equation derived from Hooke's Law

From Hook's Law, we can derived that Card 7: What is spring constant?

Spring Constant

Spring constant is defined as the ratio of the force applied on a spring to the extension of the spring. It is a measure of the stiffness of a spring or elastic object.

Card 8: Graph of Streching Force against Spring Extension

Graph of Streching Force - Extension Area below the graph = Work done

Card 9: F - x Graph and Spring Constant

F-x graph and spring constant The higher the gradient, the greater the spring constant and the harder (stiffer) spring.

For example, the stiffness of spring A is greater than spring B.

Card 10: System of Spring

System of Spring Arrangement in series:
Extension = x × number of spring
Stiffness decreases
Spring constant = k/number of spring

Arrangement in parallel:
Extension = x ÷ number of spring
Stiffness increases
Spring constant = k × number of spring

Factors Affecting the Stiffness of Spring

Factors Affecting the Stiffness of Spring

 Stiffer Less stiff Material type of spring  Diameter of wire of spring  Diameter of the spring  Length of the string   Table of Content

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