During a baseball game, a player’s ball hit into the outfield is modeled by the equation h = –16t2 + 65t. A bird flying across the field follows the path modeled by the equation h = 8t + 20. Let t be the time since the ball is hit and h be the height.
For normal goods, the income effect and the substitution effect both work in the same direction; a decrease in the relative price of the good will increase quantity demanded both because the good is now cheaper than substitute goods, and because the lower price means that consumers have a greater total purchasing power.
