For example, a guitar string made of nylon stretches when it is tightened, and the elongation. Elasticity is the property of solid materials to return to their original shape and size after the forces deforming them have been removed. My appreciation for mechanics was nucleated by professors douglas amarasekara and munidasa ranaweera of the then university of ceylon, and was subsequently shaped and grew substantially under the in uence of professors james k. Elastic goods and services generally have plenty of substitutes. Otp has been sent to your mobile number and is valid for one hour. Fluids and elasticity in this chapter we study macroscopic systems.
Theory of elasticity exam problems and answers lecture ct5141. On this page you can read or download elasticity physics notes pdf in pdf format. Newest elasticity questions physics stack exchange. For example, lets say the price of cable tv service a goes up by 10%. These forces are electrical in nature and these are active if the distance between the two. For example, say the quantity demanded rose 10% when the price fell 5%. On this page you can read or download chapter 5 elasticity physics target notes pdf in pdf format. Very elastic materials like rubber have small latex\textklatex and thus will stretch a lot with only a small force. Lecture 7 elasticity 3 physics 460 f 2006 lect 7 elasticity in cubic crystals elastic constants c ij are completely specified by 3 values c 11, c 12, c 44. For example, a stress on a rubber band produces larger strain deformation than the same.
Elasticity is a measure of how much the quantity demanded of a service or good changes in relation to its price, consumer income, or supply. Plasticity, ability of certain solids to flow or to change shape permanently when subjected to stresses of intermediate magnitude between those producing temporary deformation, or elastic behaviour, and those causing failure of the material, or rupture see yield point. To a greater or lesser extent, most solid materials exhibit elastic behaviour, but there. When the weight hung on a spring is increased by 60 n, the new stretch is 15 cm more. The purpose of this section is to develop some general rules about elasticity, which may them be applied to the four different specific types of elasticity discussed in more detail below. Theory of elasticity exam problems and answers lecture. Elastic demand e lasticity of demand is an important variation on the concept of demand. If the material is elastic, the object will return to its initial shape and size when these forces are removed. In many design problems, the loads to be applied to the structure are known at the outset, and we wish. Demand can be classified as elastic, inelastic or unitary. Metals may display elasticity as atomic lattices change shape and size, again, returning to their original form once energy is removed. Rubber band elasticity the concept of elasticity, as used in economics, is quite similar to the concept as applied to. Use a model of the microscopic structure of materials to explain.
In the engineering literature, the modulus of elasticity is often denoted as e. L is proportional to the force applied at least for small deformations. This tutorial contains plenty of examples and practice problems. A body with this ability is said to behave or respond elastically. Calculate the price elasticity of demand and draw the graph. Elasticity if an external force is applied to a material, it causes deformation in molecular structure of that material. Discuss the three types of deformations such as changes in length, sideways shear and changes in volume. Elasticity, ability of a deformed material body to return to its original shape and size when the forces causing the deformation are removed. Application to the physics of condensed matter by dresselhaus, dresselhaus, and jorio, the irreducible. When the weight is removed, the spring will return to its original shape or length. Solid objects will deform when adequate forces are applied to them. For example, f 100 hz is representative of the gravitational waves. If the deformation, or strain the ratio of the change in length to the initial length, is.
Jun 21, 2016 on this page you can read or download chapter 5 elasticity physics target notes pdf in pdf format. By removing this force, material turns its original shapes. If the material is elastic, the object will return to its initial shape. Modeling clay, on the other hand, is relatively inelastic and retains a new shape even after the force that caused it to change is no longer being exerted. Elasticity is independent of the units used to measure price and quantity. Lecture 7 elasticity 1 physics 460 f 2006 lect 7 1 elasticity stress and strain in crystals kittel ch 3 physics 460 f 2006 lect 7 2 elastic behavior is the fundamental distinction between solids and liquids similartity. Perfectly elastic demand is when the quantity demanded skyrockets to infinity when the price drops. In other words it is a measure of how small latex\textklatex is. Elasticity of demand describes the responsiveness of quantity demanded of a good relative to a small change in price. Explain hookes law using graphical representation between deformation and applied force.
Each of the equations for the elasticity of demand measures the relationship between one specific factor and demand. Its unit is nm 2 or pascal and its dimensional formula is ml 1 t 2. Elasticity 5 as the stress was further increased, a point y, known as the yield point, at which the stress rapidly dropped, was reached. Estimating elasticity a constantelasticity demand function can be written as q ap. Pa this longitudinal modulus of elasticity is called youngs modulus and is denoted by the symbol. Compressibility of a material is the reciprocal of its bulk modulus of elasticity. Nov 04, 2017 elastic modulus and the shear modulus is the ratio of stress and strain. Elasticity is a measure of how difficult it is to stretch an object. The poisons coefficient of the material is the linear expansion coefficient of the material is questions a derive an expression for the plate which relates the stress on the edge of the hole to the displacement of this edge. Elasticity is the ability of materials to return to their original shape after a deforming stretching, compressing, shearing, bending force has been removed. The more elastic a good is, the more quantity demanded will increase relative. Plasticity, as the name of a science, refers either to mathematical descriptions of what happens in plastic deformation in terms of stresses, strains, and loads or to physical explanations of plastic flow in terms of atoms, crystals, grains, and motions of structural defects dislocations within crystals.
Apr 15, 2020 for example, the elasticity of polymers and rubbers is caused by stretching polymer chains under an applied force. The bending of beams, deflection of rods, or in general, applications of hookes law generalized to three dimensions. Stress is a measure of the force put on the object over the area. Article would benefit from explaining difference between elasticity in physics and common use the physical definition of elasticity is unfortunately very different from the common usage of the word. If the original stretch is 5 cm, what is the original weight. Physics 3 summer 1989 lab 7 elasticity theory all materials deform to some extent when subjected to a stress a force per unit area. Hand a bigger weight, the spring will stretch even more. At, we provide access to the bestquality, bestvalue private tutoring service possible, tailored to your course of study. Stress, strain, and elastic modulus part 1 physics.
Stress nine quantities are required to define the state of stress at a point. The proportionality constant k depends upon a number of factors for the material. Mar 16, 2020 elastic demand is when the percentage change in the quantity demanded exceeds the percentage change in price. On the other hand, a small elastic modulus means that stress produces large strain and noticeable deformation. So, the plug is replaced by a stress on to the edge of the hole.
Pdf the dynamics of price elasticity of demand in the. Describe with examples the youngs modulus, shear modulus and bulk modulus. Elastic materials have internal forces which restore the size and shape of the object when the stress is removed. As an elastic servicegoods price increases, the quantity demanded of that good can drop quickly. For example, a steel beam reacts differently to stress than a bungee cord. We also acknowledge previous national science foundation support under grant numbers 1246120, 1525057. This longitudinal modulus of elasticity is called youngs modulus. For example, the elasticity of demand for latte is 2.
Forces, elasticity, stress, strain and youngs modulus handout pdf. So if according to the teacher, steel is very elastic with a high modulus, then. A block of gelatin is 60 mm by 60 mm by 20 mm when unstressed. Recall that the elastic moduli have dimensions of force per area. Plasticity enables a solid under the action of external forces to undergo permanent deformation without rupture. Elastic modulus and the shear modulus is the ratio of stress and strain. Apr 22, 2019 it is defined as the ratio of tangential stress to the shearing strain, within the elastic limit. Recall hookes law first stated formally by robert hooke in the true theory of elasticity or springiness 1676 which can be translated literally into as extension, so force. Plastic bodies do not show a tendency to recover to their original configuration when you remove the deforming forces. Because consumers can easily switch to lessexpensive cable tv service b or other forms.
Hookes law tells us that,for an object stresskstrain under elastic limits now, only for springs, hookes lawrestoring forcekx for all other objects undergoing tensile. Elastic demand is when the percentage change in the quantity demanded exceeds the percentage change in price. Elasticity allows us to compare the demands for different goods. Rubber bands and elastic and other stretchy materials display elasticity. Elasticity part 1 classroom lecture by pradeep kshetrapal.
Learn vocabulary, terms, and more with flashcards, games, and other study tools. Elasticity, stress, strain, and fracture boundless physics. It is the ability of returning its original shape after removing the applied stress. Elasticity of demand is the ratio of two percentages and so elasticity is a number with no units.
Microsoft powerpoint chapter15 compatibility mode author. Investigations of possible changes in the elasticity of bones in the. Elasticity is the property of a body to recover its original configuration shape and size when you remove the deforming forces. The forces between the atoms due to electrostatic interaction between the charges of the atoms are called interatomic forces. Questions tagged elasticity ask question questions related to the continuum mechanics division of elasticity. Theory, applications, and numerics, third edition, continues its marketleading tradition of concisely presenting and developing the linear theory of elasticity, moving from solution methodologies, formulations, and strategies into applications of contemporary interest, such as fracture mechanics, anisotropic and composite materials. It is defined as the ratio of tangential stress to the shearing strain, within the elastic limit. Introduction to elasticity david roylance department of materials science and engineering massachusetts institute of technology cambridge, ma 029. If you dont see any interesting for you, use our search form on bottom v. The simplest way to apply the above two concepts in an equation is to simply divide the how much the band stretches the change in the length by the change in the force. A measurement of the elasticity of a material is called the youngs modulus, and is. Just confront 100 people on the street with the statement that quartz is the most elastic material in the world.
The causes of elasticity vary depending on the type of material. We will need some algebra and a proportion to solve this tough word problem. Polymers, including rubber, may exhibit elasticity as polymer chains are stretched and then subsequently return to their original form when the force is removed. Find the shearing stress, shearing strain and shear modulus. Real rigid bodies are elastic we can slightly change their dimensions by pulling, pushing, twisting or compressing them. In contrast, the elasticity of metals is caused by resizing and reshaping the crystalline cells of the lattices which are the material structures of metals under the action of externally applied forces. Thicker nylon strings and ones made of steel stretch less for the same applied force, implying they have a larger k see figure 2. While there are several types of elasticity in economics see below, the most commonly used is demand elasticity aka price elasticity, which shows how consumer demand is affected when prices go up or down. I thought k youngs modulus was only high when the material was highly elastic. The dynamics of price elasticity of demand in the presence of reference price effects article pdf available in journal of the academy of marketing science 331. Aa spring spring is an example of an elastic body that.
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