Q2 Z2,(Q2) Z2(Q2) - Institute for Water Resources - U.S. Army

cars in the train are identical; (2) all locomotive units on a ,given
train are identical; (3) eath freight car contains the same amount
of cal%4o weight as each of the others in a given train; (4) freight
cars are weight-limited rather than space-limited; another way of
stating this is that the commodities being transported are so dense
that the load limit of a freight car is reached before its cubic
capacity is exhausted. 16 These assumptions permit the following
simplification of the speed and cargo functions:
V = h(HPNa N L)
f L' L' L" s c ' c' a c" k
(5.36)
C = N c kL. (5.37)
With the aid of a production function, one may examine the ef-
fect of the individual inputs on the productive unit's output, given
constant levels of the other inputs. In the economist's parlance,
productivity relationships may be investigated. One is concerned
with the total, average, or marginal productivity of the productive
unit with respect to a particular input. In addition, the substi-
tution possibilities between inputs may be investigated through the
production function. That is, isoquants may be determined. From
these and the related input costs, expansion paths and cost func-
tions may be obtained.
These properties of a production function may be determined
analytically if the production function relation is sufficiently
simple to permit this. Functional forms may be obtained for such
things as productivity curves, isoquants, and expansion paths.
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