Transcript DEMAND DAN SUPPLY - Pengantar Ilmu Ekonomi

PENGANTAR ILMU EKONOMI
DEMAND DAN SUPPLY
MENU
•
•
•
•
•
Demand
Wants,Needs And Demand
Faktor-Faktor Yang Mempengaruhi
Demand
Supply
Faktor-Faktor Yang Mempengaruhi
supply
DEMAND FUNCTION

To demand something, you must:
• Want it
• Be able to afford it
• Have a definite plan to buy it (Wonderling,
2005)
DEMAND FUNCTION
Wants are the unlimited desires or wishes
that people have for goods and services.
 How many times have you thought that you
would like something ‘if only you could afford it’
or ‘if it weren’t so expensive’?
 When we make choices, scarcity guarantees that
many – perhaps most – of our wants will never be
satisfied.
 Demand reflects our plans about which
wants to satisfy.

DEMAND FUNCTION
Need
Wants Demand
Demand adalah hubungan antara
harga barang dan jumlah permintaan
barang
DEMAND FUNCTION
Permintaan adalah keinginan yang disertai
kemampuan untuk membeli barang dan jasa
pada tingkat harga dan waktu tertentu.
 The term ‘demand’ is used to describe the amount
of money purchasers are prepared to pay for a
commodity.

DEMAND FUNCTION

1.
2.
3.
Hal Penting dalam Permintaan:
Kuantitas yang diminta merupakan kuantitas
yang diinginkan
Keinginan konsumen disertai oleh kemampuan
serta kesediaan untuk membeli (Permintaan
efektif)
Kuantitas yang diminta dinyatakan dalam
satuan waktu
THE LAW OF DEMAND

The law of demand states:
Other things remaining the same (Ceteris
Paribus), the higher the price of a good, the
smaller is the quantity demanded.
KURVA DEMAND
Price
Quantity
DEMAND CURVE AND DEMAND SCHEDULE
Before going any further, you need to understand
a critical distinction between demand and
quantity demanded.
 The term demand refers to the entire relationship
between the quantity demanded and the price of a
good, illustrated by the demand curve and the
demand schedule.
 The term quantity demanded refers to the exact
quantity demanded at a particular price, or a
particular point on a demand curve.

DEMAND CURVE AND DEMAND
SCHEDULE
Demand Schedule :
A table that shows the relationship between the
price of a good and the quantity demanded
 Demand Curve :
A graph of the relationship between the price of a
good and the quantity demanded

A CHANGE IN DEMAND
 When
any factor that influences buying
plans, other than the price of the good,
there is a change in demand.
 Figure 2 illustrates one such change – an
increase in demand. When demand
increases, the demand curve shifts to the
right and the quantity demanded is greater
at each prices.
Price (£ per tape)
FIGURE 2: AN INCREASE IN DEMAND
E’
E
5
D’ Demand for tapes
D
4
(Walkman £30)
C’
C
3
B’
B
2
1
New demand schedule (Walkman
£30)
Demand for tapes
(Walkman £125)
1
2
3
A’
A
4
5
6
7
8
Price
(£/tape)
Quantity (millions
of tapes/week)
A’
1
7.8
B’
2
5.9
C’
3
4.7
D’
4
4.2
E’
5
3.8
Quantity (millions of tapes /week)
A CHANGE IN DEMAND
FACTORS INFLUENCING DEMAND
1 Prices of related goods
 The quantity of any goods and services that
consumers plan to buy depends in part on the
price of related goods and services. There are two
types: substitutes and complements.
2 Income
 Other things remaining the same, when income
increases, consumers buy more of most goods,
and when income decreases, they buy less of most
goods .
 Goods for which demand increases as income
increases are called normal goods.
 Goods for which demand decreases when income
increases are called inferior goods.
3 Expected future prices
 If the price of a good is expected to rise in the
future, and if the good can be stored, the
opportunity cost of obtaining the good for future
use is lower now than it will be when the price
has increased.
 So people substitute over time. They buy more of
the good before the expected price rise and the
demand for the good increases
4 Population
 Demand also depends on the size and the age
structure of the population.
 Other things remaining the same, the larger the
population, the greater is the demand for all
goods and services, and the smaller the
population, the smaller is the demand for all
goods and services.
5 Preferences
 Preferences are an individual’s attitudes towards
and tastes for goods and services .
 Preferences are shaped by past experience,
genetic factors, advertising information, religious
beliefs, and other cultural and social factors.

Changes in the factors that influence
buyers’ plans cause either:
a movement along the demand curve, or
2. a shift of the demand curve
1.
1. MOVEMENT ALONG THE DEMAND CURVE



If the price of a good changes but everything else remains the
same, there is a movement along the demand curve.
For example, if the price of a tape changes from £ 3 to £ 5,
the result is a movement along the demand curve, from point
C to point E in figure 1.
The negative slope of the demand curve reveals that a
decrease in the price of a good or service increases the
quantity demanded – the law of demand
2. A SHIFT OF THE DEMAND CURVE


If the price of a good remains constant but some other
influence on buyers’ plans changes, there is a change
in demand for that good
Figure 2 illustrates such a shift
SUPPLY
Jumlah barang dan jasa yang bersedia dan dapat
ditawarkan oleh Produsen kepada konsumen
pada setiap tingkat harga selama periode
tertentu
 Quantity supplied : the amount of a good that
sellers are willing and able to sell

HUKUM SUPPLY
Law of supply :
“the claim that, other things equal, the quantity
supplied of a good rises when the price of the good
rises”

A CHANGE IN SUPPLY
FAKTOR2 YANG MEMPENGARUHI
PERUBAHAN SUPPLY
1. Price
 the quantity supplied rises as the price rises and
falls as the price falls,
 So we say that the quantity supplied is positively
related to the price of the good
2. Input Price
 To produce its output of ice cream, Student
Sweets uses various inputs: cream, sugar,
flavoring, ice-cream machines, the buildings in
which the ice cream is made, and the labor of
workers to mix the ingredients and operate the
machines.
 When the price of one or more of these inputs
rises, producing ice cream is less profitable, and
your firm supplies less ice cream.
 If input prices rise substantially, you might shut
down your firm and supply no ice cream at all.
3. Technology
 The technology for turning the inputs into ice
cream is yet another determinant of supply. The
invention of the mechanized ice-cream machine,
for example, reduced the amount of labor
necessary to make ice cream.
 By reducing firms’ costs, the advance in
technology raised the supply of ice cream
4. Expectations
 The amount of ice cream you supply today may
depend on your expectations of the future.
 For example, if you expect the price of ice cream
to rise in the future, you will put some of your
current production into storage and supply less to
the market today.
SUPPLY SCHEDULE

Supply Schedule : a table that shows the
relationship
between the price of a good and the quantity
supplied
SUPPLY SCHEDULE
MARKET SUPPLY
The market supply is the sum of the two
individual or more supplies.
 Market supply depends on all those factors that
influence the supply of individual sellers, such as
the prices of inputs used to produce the good, the
available technology, and expectations.
 In addition, the supply in a market depends on
the number of sellers

GAMBAR 1: KURVA SUPPLY
Price
($)
S
P
2
P
1
0
Q1
Q2
Quantity
KESETIMBANGAN PASAR
(MARKET EQUILIBRIUM)
Definisi
Situasi dimana harga terbentuk pada:
Jml demand
thd barang
=
Jml barang yg
disupply
GAMBAR 2: PASAR BARANG …..
Price
($)
S
Market
Equilibri
um
P1
D
0
Q1
Quantity
TUGAS KELOMPOK
1.
2.
3.
4.
Jelaskan apa yang dimaksud dengan Excess
Demand dan Excess Supply beserta contoh ?
Jelaskan hal-hal yang menyebabkan Excess
Demand dan Excess Supply terjadi ?
Jelaskan penggolongan pembeli dan penjual di
pasar ?
Jelaskan peranan pemerintah dalam
pembentukkan harga pasar?