Consider the market for smartphones. explain whether the following events would cause an increase or a decrease in supply or an increase or a decrease in the quantity supplied. illustrate each, and show what would happen to the equilibrium quantity and the market price. a. the price of touch screens used in smartphones declines. b. the price of machinery used to produce smartphones increases. c. the number of manufacturers of smartphones increases. d. there is a decrease in the market demand for smartphones

Because of the violent nature of the sport, professional american football players are at risk of suffering concussions (or brain injuries) during the violent collisions that occur between players during the game. violent collisions involving hits to the head are particularly risky. suppose the commissioner of the national football league (nfl) institutes a rule requiring players to wear a new, lighter helmet that is designed to reduce head trauma during collisions between players on the field. while the new helmets the probability of a concussion resulting from each individual collision, at the same time the new helmets could also give football players an incentive to play more , which could potentially the amount of violent collisions and thus the number of concussions suffered by nfl players, all else equal.