1 Supply And Demand Supply And Demand Pertemuan - 3 Moh. Sigit Taruna 2009-Pengantar Ekonomi I...
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Transcript of 1 Supply And Demand Supply And Demand Pertemuan - 3 Moh. Sigit Taruna 2009-Pengantar Ekonomi I...
1
Supply
And
Demand
Supply
And
Demand
Pertemuan - 3Moh. Sigit Taruna 2009-Pengantar Ekonomi I
Pertemuan - 3Moh. Sigit Taruna 2009-Pengantar Ekonomi I
2
The Market Mechanism• The Supply Curve
– The supply curve shows how much of a good producers are willing to sell at a given price, holding constant other factors that might affect quantity supplied
– This price-quantity relationship can be shown by the equation:
)(PQQ Ss
3
The Market Mechanism• The Demand Curve
– The demand curve shows how much of a good consumers are willing to buy as the price per unit changes holding non-price factors constant.
– This price-quantity relationship can be shown by the equation:
(P)QQ DD
4
The Market Mechanism
Quantity
D
S
The curves intersect atequilibrium, or market-
clearing, price. At P0 thequantity supplied is equalto the quantity demanded
at Q0 .
P0
Q0
Price($ per unit)
5
The Market Mechanism
• The market price is above equilibrium– There is excess supply– Producers lower prices– Quantity demanded increases and quantity
supplied decreases– The market continues to adjust until the
equilibrium price is reached.
A SurplusA Surplus
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The Market Mechanism
D
S
Q1
Assume the price is P1 , then:1) Qs : Q2 > Qd : Q1 2) Excess supply is Q1:Q2.3) Producers lower price.4) Quantity supplied decreases
and quantity demanded increases.
5) Equilibrium at P2Q3
P1
Surplus
Q2 Quantity
Price($ per unit)
P2
Q3
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The Market Mechanism
• The market price is below equilibrium:– There is a shortage– Producers raise prices– Quantity demanded decreases and quantity supplied
increases– The market continues to adjust until the new
equilibrium price is reached.
ShortageShortage
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The Market Mechanism
D
S
Q1 Q2
P2
Shortage
Quantity
Price($ per unit)
Assume the price is P2 , then:1) Qd : Q2 > Qs : Q1
2) Shortage is Q1:Q2.3) Producers raise price.
4) Quantity supplied increases and quantity demanded decreases.
5) Equilibrium at P3, Q3
Q3
P3
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Supply and Demand• Non-price Determining Variables of Supply
– Costs of Production• Labor
• Capital
• Raw Materials
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Supply and Demand
• The cost of raw materials falls
– At P1, produce Q2
– At P2, produce Q1
– Supply curve shifts right to S’
– More produced at any price on S’ than on S
P S
Change in SupplyChange in Supply
Q
P1
P2
Q1Q0
S’
Q2
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Changes In Market Equilibrium (Supply Curve)
• Jika biaya turun, harga (P) dan jumlah (Q) tidak selalu konstan
• Akan terjadi perubahan, jika supply curve yang baru mencapai ekuilibrium dengan demand curve
• Supply curve akan menggeser, maka harga pasar akan jatuh dan jumlah produksi naik
• Maka biaya yang rendah menghasilkan harga yang lebih rendah dan penjualan meningkat.
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S’
Q2
• Raw material prices fall
– S shifts to S’
– Surplus @ P1 of Q1, Q2
– Equilibrium @ P3, Q3
P
Q
SD
P3
Q3Q1
P1
Changes In Market Equilibrium
13
Supply and Demand• Non-price Determining Variables of
Demand– Income– Consumer Tastes– Price of Related Goods
• Substitutes• Complements
14
DP
QQ1
P2
Q0
P1
D’
Q2
Change in DemandChange in Demand
Supply and Demand
• Income Increases– At P1, produce Q2
– At P2, produce Q1
– Demand Curve shifts right
– More purchased at any price on D’ than on D
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D’ SD
Q3
P3
Q2
• Income Increases
– Demand shifts to D1
– Shortage @ P1 of Q1, Q2
– Equilibrium @ P3, Q3
P
QQ1
P1
Changes In Market Equilibrium
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D’ S’• Income Increases & raw material prices fall
– The increase in D is greater than the increase in S
– Equilibrium price and quantity increase to P2, Q2
P
Q
S
P2
Q2
D
P1
Q1
Changes In Market Equilibrium
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Elasticity• Elasticity is a general concept that
can be used to quantify the response in one variable when another variable changes.
• Seberapa besar perubahan jumlah yang diminta sebagai akibat dari perubahan harga
Pertemuan - 6Moh. Sigit Taruna 2009
Pertemuan - 6Moh. Sigit Taruna 2009
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Permintaan Elastis dan Inelastis
• Elastis : bila jumlah yang diminta sangat peka terhadap perubahan harga
• Inelastis : bila jumlah yang diminta kurang peka terhadap perubahan harga
• Price elastic demand : perubahan harga sebesar 1% menyebabkan perubahan jumlah yang diminta lebih dari 1%
• Price inelastic demand :perubahan harga sebesar 1% menyebabkan perubahan jumlah yang diminta kurang dari 1%
19
Price Elasticity of Demand
• A popular measure of elasticity isA popular measure of elasticity is price elasticity of demand price elasticity of demand measures how responsive measures how responsive consumers are to changes in the consumers are to changes in the price of a product.price of a product.
• The value of demand elasticity is always negative, but it is stated in absolute terms.
P rice e las tic ity o f d em an d =P ercen tag e ch an g e in q u an tity d em an d ed
P ercen tag e ch an g e in p rice
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Elasticities of Supply and Demand
• Income elasticity of demand measures the percentage change in quantity demanded resulting from a one percent change in income.
Other Demand ElasticitiesOther Demand Elasticities
I
Q
Q
I
I/I
Q/Q EI
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Price Elasticity of Demand
PX
QX
MRX
1PE
1PE
1PE Elastis Uniter
Inelastis
Elastis
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Perfectly Elastic andPerfectly Inelastic Demand Curves
• When demand does not respond at all to a change in price, demand is perfectly inelastic.
• Demand is perfectly elastic when quantity demanded drops to zero at the slightest increase in price.
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Elasticities of Supply and Demand
• Price elasticity of supply measures the percentage change in quantity supplied resulting from a 1 percent change in price.
• The elasticity is usually positive because price and quantity supplied are directly related.
Elasticities of SupplyElasticities of Supply
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Elasticities of Supply and Demand
• We can refer to elasticity of supply with respect to interest rates, wage rates, and the cost of raw materials.
Elasticities of SupplyElasticities of Supply
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Elasticities of Supply and Demand
• 1981 Supply Curve for Wheat– QS = 1,800 + 240P
• 1981 Demand Curve for Wheat– QD = 3,550 - 266P
The Market for WheatThe Market for Wheat
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Elasticities of Supply and Demand
• Equilibrium: Q S = Q D
PP 266550,3240800,1
750,1506 P
bushelP /46.3
bushels million 630,2)46.3)(240(800,1 Q
The Market for WheatThe Market for Wheat
Chapter 2: The Basics of Supply and Demand Slide 26
27
Elasticities of Supply and Demand
Inelastic 35.0)266(630,2
46.3
P
Q
Q
PE DD
P
Inelastic 32.0)240(630,2
46.3
P
Q
Q
PE SS
P
The Market for WheatThe Market for Wheat
Chapter 2: The Basics of Supply and Demand Slide 27
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Elasticities of Supply and Demand
• Assume the price of wheat is $4.00/bushel
486,2)00.4)(266(550,3 DQ
43.0)266(486,2
00.4D
PE
The Market for WheatThe Market for Wheat
29
1981 1,800 + 240P 3,550 - 266P 1,800+240P = 3,550-266P506P = 1750
P1981 = $3.46/bushel
1998 1,944 + 207P 3,244 - 283P 1,944+207P = 3,244-283P P1998 = $2.65/bushel
Supply (Qs) Demand (QD) Equilibrium Price (Qs = QD)
Changes in the Market: 1981-1998The Market for WheatThe Market for Wheat
www.sigittaruna.wordpress.com
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Short-Run Versus Long-Run Elasticities
• Price elasticity of demand varies with the amount of time consumers have to respond to a price.
DemandDemand
32
• Most goods and services:– Short-run elasticity is less than long-run
elasticity. (e.g. gasoline, Drs.)
• Other Goods (durables):– Short-run elasticity is greater than long-run
elasticity (e.g. automobiles)
Short-Run Versus Long-Run Elasticities
DemandDemand
33
Gasoline: Short-Run andLong-Run Demand Curves
DSR
DLR
People tend to drive smaller and more fuel efficient
cars in the long-run
Gasoline
Quantity
Price
34
DSR
DLR
People may putoff immediate
consumption, buteventually older cars
must be replaced.
Automobiles
Automobiles: Short-Run andLong-Run Demand Curves
Quantity
Price
35
• Most goods and services:– Long-run price elasticity of supply is greater
than short-run price elasticity of supply.
• Other Goods (durables, recyclables):– Long-run price elasticity of supply is less than
short-run price elasticity of supply
Short-Run Versus Long-Run Elasticities
SupplySupply
36
SSR
Primary Copper: Short-Run and Long-Run Supply Curves
Primary Copper: Short-Run and Long-Run Supply Curves
Quantity
Price
Short-Run Versus Long-Run Elasticities
SLR
Due to limitedcapacity, firmsare limited by
output constraintsin the short-run.
In the long-run, theycan expand.
37
SSR
Secondary Copper: Short-Run and Long-Run Supply Curves
Secondary Copper: Short-Run and Long-Run Supply Curves
Quantity
Price
Short-Run Versus Long-Run Elasticities
SLR
Price increasesprovide an incentive
to convert scrapcopper into new supply.
In the long-run, thisstock of scrap copper
begins to fall.
38
D
S
P0
Q0 Quantity
Price
P1
Short-Run1) Supply is completely inelastic2) Demand is relatively inelastic3) Very large change in price
A freeze or drought decreases the supply
of coffee
S’
Q1
Short-Run Versus Long-Run Elasticities
CoffeeCoffee
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S’
D
S
P0
Q0
P2
Q2
Intermediate-Run1) Supply and demand are more elastic2) Price falls back to P2.3) Quantity falls to Q2
Short-Run Versus Long-Run Elasticities
Quantity
Price
CoffeeCoffee
40
D
SP0
Q0
Long-Run1) Supply is extremely elastic.2) Price falls back to P0.3) Quantity increase to Q0.
Short-Run Versus Long-Run Elasticities
CoffeeCoffee
Quantity
Price
41
• First, we must learn how to “fit” linear demand and supply curves to market data.
• Then we can determine numerically how a change in a variable will cause supply or demand to shift and thereby affect the market price and quantity.
Understanding and Predicting the Effects of Changing Market Conditions
42
• Available Data– Equilibrium Price, P*– Equilibrium Quantity, Q*– Price elasticity of supply, ES, and demand,
ED.
Understanding and Predicting the Effects of Changing Market Conditions
43
Demand: Q = a - bP
a/bSupply: Q = c + dP
-c/d
P*
Q*
ED = -bP*/Q*ES = dP*/Q*
Understanding and Predicting the Effects of Changing Market Conditions
Quantity
Price
44
Effects of Government Intervention --Price Controls
• If the government decides that the equilibrium price is too high, they may establish a maximum allowable ceiling price.
45
D
Effects of Price Controls
Quantity
Price
P0
Q0
S
Pmax
Excess demand
If price is regulated tobe no higher than Pmax,quantity supplied falls
to Q1 and quantitydemanded increases toQ2. A shortage results
46
Price Controls andNatural Gas Shortages
• In 1954, the federal government began regulating the wellhead price of natural gas.
• In 1962, the ceiling prices that were imposed became binding and shortages resulted.
• Price controls created an excess demand of 7 trillion cubic feet.
• Price regulation was a major component of U.S. energy policy in the 1960s and 1970s, and it continued to influence the natural gas markets in the 1980s.