need help please!

Consider the Tobin's q model of capital valuation. A firm with installed capital k(t) will be worth v(t) = q(t)k(t) where q(t) is the price of an installed unit of capital. Using the phase diagram below, describe the effects of each of the following changes on ?k = 0 and ?q = 0, on K and q at the time of the change, and on their behaviour over time. In each case assume that K and q are initially at their long-run equilibrium values.

(a) A war destroys half of the capital stock.

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