The following market demand and firm cost condi- tions describe a perfectly competitive industry:

p = 100 0.0005Q

T C = 10q 0.1q2 + 0.0005q3

(a) Find the firms short-run supply function. (2)

(b) Explain the firm's shutdown rule. (4)

(c) Suppose we are on the short-run and the num- ber of firms is 1000. Determine the equilib- rium price (p), market output (Q), and firm output (q). Briefly explain whether there will be entry or exit in the long run. (8)

(d) Determine the long-run equilibrium price (p), market output (Q), firm output (q) and number of identical firms (N).