The short run aggregate supply curve was constructed assuming that as the price of outputs increases, the price of inputs stays the same. How would an increase in the prices of important inputs, like energy, affect aggregate supply?
Higher input prices make output less profitable, decreasing the desired supply. This is shown graphically as a leftward shift in the AS curve.
In the AD/AS model, what prevents the economy from achieving equilibrium at potential output?
Equilibrium occurs at the level of GDP where AD = AS. Insufficient aggregate demand could explain why the equilibrium occurs at a level of GDP less than potential. A decrease (or leftward shift) in aggregate supply could be another reason.