Answer:
a. The production function in the Solow growth model is Y = F(K, L), or expressed in terms of output per worker, y = f(k). If a war reduces the labor force through casualties, then L falls but k = K/L rises. The production function tells us that total output falls because there are fewer workers. Output per worker increases, however, since each worker has more capital.
b. The reduction in the labor force means that the capital stock per worker is higher after the war.