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Econ 100 Lecture 2.3. Supply Curves 10-7-2010. Figure 4.8 The Individual Firm Supply Schedule and Curve. Supply curve is a marginal cost (MC) curve. Market Supply. The market supply curve is the horizontal sum of all the individual firm supply curves.
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Econ 100Lecture 2.3 Supply Curves 10-7-2010
Figure 4.8 The Individual Firm Supply Schedule and Curve Supply curve is a marginal cost (MC) curve
Market Supply • The market supply curve is the horizontal sum of all the individual firm supply curves.
Figure 4.9 The Supply of Coffee in the City of Burlington, Vermont
Changes in Supply • Factors that affect the supply of a good: • Prices of inputs (such as wages) • Technology • Natural disruptions (such as bad weather) • The number of firms in the market • Expectations • Government policies
Equilibrium • The combined forces of supply and demand in a market determine: • The quantity of a product bought and sold, and • The price per unit of the product. • The equilibrium price is the price at which: • The quantity demanded equals the quantity supplied and the market “clears.”
Equilibrium (cont’d) • When a market is in equilibrium, there will be no tendency for price or quantity to change.
The Cobweb Theorem Price (£) S The price falls to £5 and farmers react by cutting plans for turkey production. Ten months later, supply on the market will be 8 million. Farmers respond by planning to increase supply, ten months later, the supply of turkeys is 15 million. At this level, there will be a surplus of turkeys and the price drops. Assume the initial equilibrium price is £7 and the quantity 9. If demand rises, the shortage pushes the price up to £11 per turkey. This creates a massive shortage of 9 million turkeys and the price is forced up – and so the process continues! A divergent cobweb leads to price instability over time. In a ‘divergent cobweb’ -also termed an unstable cobweb - the price tends to move away from equilibrium. 11 7 5 D1 D 8 9 15 17 Quantity Bought and Sold (millions)
Cobweb Theorem • http://www.bized.co.uk/current/mind/2004_5/251004.ppt • Hungarian-born economist Nicholas Kaldor (1908-1986) • Simple dynamic model of cyclical demand with time lags between the response of production and a change in price (most often seen in agricultural sectors). • Cobweb theory is the process of adjustment in markets • Traces the path of prices and outputs in different equilibrium situations. Path resembles a cobweb with the equilibrium point at the center of the cobweb. • Sometimes referred to as the hog-cycle (after the phenomenon observed in American pig prices during the 1930s).
Some Questions to Ponder • An early freeze destroys half of Florida’s orange crop. • What will be the impact on the price of OJ? • On the price of meals that include OJ as part of the package? • Import quotas restrict the quantity of particular goods, e.g., large screen TVs, that can be imported from a given country • What is the impact on the US market of restricting TVs imported from China? • What is the impact on the US housing market of restricting “illegal” immigrants who provide construction labor? Or harvest agricultural products, like apples? • How does a sales tax, e.g., 10% of the purchase price, affect the demand for those goods or services? • How does a subsidy, e.g., a 10% rebate, affect the demand for those goods and services? How would a subsidy for “green energy”, e.g. biodiesel fuels, affect: a) the demand for biodiesel fuels? b) the demand for gasoline, c) the demand for corn (from which biodiesel is produced)? • Seattle is considering two alternatives to the Alaska Way Viaduct. 1) A tunnel (2 lanes each way) and 2) a surface street. One proponent of the surface street option has said that it will encourage more people to use buses and reduce car travel. Is she correct?
Useful Websites • Understanding differences between factors that cause shifts in demand or supply • http://hspm.sph.sc.edu/COURSES/ECON/SD/SD.html • Basics of demand and supply • http://www.investopedia.com/university/economics/economics3.asp • Cobweb theorem • http://www.bized.co.uk/current/mind/2004_5/251004.ppt