A change in the price level (for example brought about by a shift in AD) results in a movement along the short run aggregate supply curve. The slope of SRAS curve depends on the degree of spare (under-utilised) capacity within the economy.
Supply and demand
In microeconomics, the theory of consumer choice relates preferences (for the consumption of both goods and services) to consumption expenditures; ultimately, this relationship between preferences and consumption expenditures is used to relate preferences to consumer demand curves. The link between personal preferences, consumption, and the demand curve is one of the most closely studied relations in economics. Consumer choice theory is a way of analyzing how consumers may achieve equilibrium between preferences and expenditures by maximizing utility as subject to consumer budget constraints.]citation needed[
Preferences are the desires by each individual for the consumption of goods and services that translate into choices based on income or wealth for purchases of goods and services to be combined with the consumer's time to define consumption activities. Consumption is separated from production, logically, because two different consumers are involved. In the first case consumption is by the primary individual; in the second case, a producer might make something that he would not consume himself. Therefore, different motivations and abilities are involved. The models that make up consumer theory are used to represent prospectively observable demand patterns for an individual buyer on the hypothesis of constrained optimization. Prominent variables used to explain the rate at which the good is purchased (demanded) are the price per unit of that good, prices of related goods, and wealth of the consumer.
Long run and short run
In microeconomics, supply and demand is an economic model of price determination in a market. It concludes that in a competitive market, the unit price for a particular good will vary until it settles at a point where the quantity demanded by consumers (at current price) will equal the quantity supplied by producers (at current price), resulting in an economic equilibrium for price and quantity.
The four basic laws of supply and demand are::37
In microeconomics, the long run is the conceptual time period in which there are no fixed factors of production as to changing the output level by changing the capital stock or by entering or leaving an industry. The long run contrasts with the short run, in which some factors are variable and others are fixed, constraining entry or exit from an industry. In macroeconomics, the long run is the period when the general price level, contractual wage rates, and expectations adjust fully to the state of the economy, in contrast to the short run when these variables may not fully adjust.
The IS–LM model (nvestmentI avingS–iquidity PreferenceL oney SupplyM) is a macroeconomic tool that demonstrates the relationship between interest rates and real output, in the goods and services market and the money market. The intersection of the IS and LM curves is the "general equilibrium" where there is simultaneous equilibrium in both markets.
The AD–AS or aggregate demand–aggregate supply model is a macroeconomic model that explains price level and output through the relationship of aggregate demand and aggregate supply. It is based on the theory of John Maynard Keynes presented in his work The General Theory of Employment, Interest, and Money. It is one of the primary simplified representations in the modern field of macroeconomics, and is used by a broad array of economists, from libertarian, Monetarist supporters of laissez-faire, such as Milton Friedman to Post-Keynesian supporters of economic interventionism, such as Joan Robinson.
The conventional "aggregate supply and demand" model is, in actuality, a Keynesian visualization that has come to be a widely accepted image of the theory. The Classical supply and demand model, which is largely based on Say's law, or that supply creates its own demand, depicts the aggregate supply curve as being vertical at all times (not just in the long-run)
In economics, aggregate supply is the total supply of goods and services that firms in a national economy plan on selling during a specific time period. It is the total amount of goods and services that firms are willing to sell at a given price level in an economy.]citation needed[
There are two main reasons why Qs might rise as P rises, i.e., why the AS curve is upward sloping: