Rubber elasticity, identified as the capacity to sustain very large deformations followed by complete recovery, is exhibited exclusively by polymeric substances consisting predominantly of long molecular chains. Moreover, it is manifested under suitable conditions by virtually all polymers so constituted.
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How do you calculate elasticity of rubber?
The relationship is expressed by the equation F/M=(L−1−L−2) exp A(L−L−1) where F is the stress, L the ratio of stretched to unstretched length, and M and A are constants. The constant M depends on the nature of the rubber, the extent of vulcanization, and the time of creep. The constant A has a value of about 0.38.
What causes elasticity in rubber?
Natural rubber is made of long chains of molecules called polymers. Because these polymers are so long (they can be thousands of molecules long) they get tangled up in themselves. The result is a property called elasticity, the polymers are elastic.
What is meant by elasticity in physics?
elasticity, ability of a deformed material body to return to its original shape and size when the forces causing the deformation are removed. A body with this ability is said to behave (or respond) elastically. Hooke’s law.
Is rubber elastic or inelastic?
It is this constant jostling that produces a resisting (elastic) force in the chains as they are forced to become straight. While stretching a rubber sample is the most common example of elasticity, it also occurs when rubber is compressed.
What are the properties of rubber?
Rubber is water repellent and resistant to alkalies and weak acids. Rubber’s elasticity, toughness, impermeability, adhesiveness, and electrical resistance make it useful as an adhesive, a coating composition, a fiber, a molding compound, and an electrical insulator.
How do you calculate elasticity in physics?
How do you measure elasticity?
How to Calculate Price Elasticity. To calculate price elasticity, divide the change in demand (or supply) for a product, service, resource, or commodity by its change in price.
What is the modulus of elasticity of a rubber band?
Young’s modulus is a great way to tell how elastic a material is. Very elastic materials, like rubber bands, will have a relatively small Young’s modulus because they exhibit a high strain in response to a relatively low stress. A typical Young’s modulus value for rubber is 0.01 GPa.
How does rubber lose elasticity?
The rubber bands lose their elasticity because the polymers and plasticizers in rubber begin to oxidize over time, and exposure to ozone (which is present in all air to some degree) is largely responsible for this oxidization battle with rubber.
How does temperature affect the elasticity of rubber?
Thermal expansion caused the rubber bands to react as they did. When the rubber bands were heated, the particles stretched out, making them more elastic and able to withstand greater force. When frozen, the particles contracted, adding strength and decreasing resistance to force.
How can you reduce the elasticity of rubber?
Shrinking Rubber Using Hot Water. Run hot water over the rubber. At first, try using tap water. If the rubber is weak enough, the water will eventually force the rubber to contract and shrink.
What are the 3 types of elasticity in physics?
There are three types of modulus of elasticity namely Young’s modulus, shear modulus and bulk modulus.
What are the 4 types of elasticity?
Four types of elasticity are demand elasticity, income elasticity, cross elasticity, and price elasticity.
Why is rubber more elastic than steel?
The strain produced in rubber is much larger compared to that in steel. This means that steel has a larger value of Young’s modulus of elasticity and hence, steel has more elasticity than rubber. Note: Greater the resistance to change, greater is the elasticity of that material.
Is rubber more elastic than plastic?
Detailed Solution. Concept: Elasticity is the property of a material to regain its original shape after deformation when the external forces are removed. All materials are plastic to some extent but the degree varies, for example, both mild steel and rubber are elastic materials but steel is more elastic than rubber.
Is rubber elastic or plastic?
Rubbers are elastomers, these are polymers with an elastic property. This elasticity differentiates rubbers from plastics. Elastic means that the material can be stretched and, when released, returns to within at least 90% of its original dimensions and shape within a period of time, at room temperature.
What are the mechanical properties of rubber?
- Tensile strength.
- Elongation.
- Modulus.
- Compression set.
- Cut and tear resistance.
- Abrasion resistance.
- Crack growth and fatigue resistance.
- Thermal and weather aging.
What are the two types of rubber?
There are two primary types of rubber, namely natural rubber and synthetic rubber.
What is the tensile strength of rubber?
A piece of rubber measuring 90 on a Shore A gauge will read around 42-43 on a Shore D gauge. Ultimate tensile strength, or just tensile strength, is the maximum force a material can withstand without fracturing when stretched. It is the opposite of compressive strength.
What is the formula for elastic force?
Hooke’s law gives us the force we need to find elastic potential energy. Looking at a graph of force versus displacement, we can find that the formula for elastic potential energy is PE = 1/2(kx^2).
What is elastic limit formula?
Mathematically, Hooke’s law states that the applied force F equals a constant k times the displacement or change in length x, or F = kx. The value of k depends not only on the kind of elastic material under consideration but also on its dimensions and shape.
What is elastic force example?
When someone jumps on a trampoline, he/she exerts pressure in the downward direction. In response to this externally exerted force, a counterforce called elastic force gets developed in the upward direction. Therefore, this elastic force helps the person to bounce.
What are two methods of measuring elasticity?
There are four methods of measuring elasticity of demand. They are the percentage method, point method, arc method and expenditure method.
What is the unit for measuring elasticity?
The units of modulus of elasticity are pressure units, as it is defined as stress (pressure units) divided by strain (dimensionless). Most commonly the units are Pascals (Pa) which is the SI unit, or pounds per square inch (psi) depending on the industry or geographical location.